High Court's Jurisdiction Limits: RIPA 2000 & Investigatory Powers Tribunal, Study Guides, Projects, Research of Law

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Easter Term [2019] UKSC 22 On appeal from: [2017] EWCA Civ 1868 JUDGMENT R (on the application of Privacy International) (Appellant) v Investigatory Powers Tribunal and others (Respondents) before Lady Hale, President Lord Reed, Deputy President Lord Kerr Lord Wilson Lord Sumption Lord Carnwath Lord Lloyd-Jones JUDGMENT GIVEN ON 15 May 2019 Heard on 3 and 4 December 2018 Appellant Respondent Sir Jeffrey Jowell QC Jonathan Glasson QC Dinah Rose QC Ben Jaffey QC Tom Cleaver Gayatri Sarathy (Instructed by Bhatt Murphy Solicitors) (Instructed by The Government Legal Department) Interested Parties Sir James Eadie QC Kate Grange QC Catherine Dobson James Bradford (Instructed by The Government Legal Department) (Intervener - Liberty) Martin Chamberlain QC David Heaton (Instructed by Liberty) Respondent: (1) Investigatory Powers Tribunal – written submissions only Interested Parties: (2) Secretary of State for Foreign and Commonwealth Affairs and Government Communications Headquarters Page 4  the use of covert human intelligence sources (agents, informants, undercover officers);  access to encrypted data.” For each of these powers, it was said, the Act would ensure that the law would clearly cover the purposes for which they could be used, by whom and with whose authority, the use that could be made of the material gained, and also “independent judicial oversight”, and means of redress for individuals. 5. The statutory provisions governing the composition, jurisdiction and procedures of the IPT are complex. There is a comprehensive account in the judgment of Sir Brian Leveson P in the Divisional Court (paras 5 to 15) ([2017] EWHC 114 (Admin)). For present purposes it is enough to note the principal features. Section 65(1) and Schedule 3 deal with its composition. The number of members is set by Her Majesty by Letters Patent (section 65(1)). The President must have held high judicial office, and the other members must have held high judicial office or meet specified legal qualifications. In the present case the tribunal consisted of five members presided over by Burton J (President) and Mitting J (Vice- President), the others all being leading counsel. 6. As to its jurisdiction section 65(2) provides: “(2) The jurisdiction of the tribunal shall be - (a) to be the only appropriate tribunal for the purposes of section 7 of the Human Rights Act 1998 in relation to any proceedings under subsection (1)(a) of that section (proceedings for actions incompatible with Convention rights) which fall within subsection (3) of this section; (b) to consider and determine any complaints made to them which, in accordance with subsection (4), are complaints for which the tribunal is the appropriate forum; (c) to consider and determine any reference to them by any person that he has suffered detriment as a consequence of any prohibition or restriction, by virtue Page 5 of section 17, on his relying in, or for the purposes of, any civil proceedings on any matter; and (d) to hear and determine any other such proceedings falling within subsection (3) as may be allocated to them in accordance with provision made by the Secretary of State by order.” 7. The remainder of section 65 provides further details of these four categories of jurisdiction, which are not material in the present case. It is to be noted that the jurisdiction of the IPT may depend on uncertain issues of law or fact. For example, in C v The Police IPT/03/32/H the IPT considered a complaint by a retired police officer alleging that there had been unlawful covert surveillance in breach of article 8 of the European Convention on Human Rights (“the Convention”) by his former police force. The essential facts were agreed, but the IPT held that it had no jurisdiction to consider his complaint because there was no “directed surveillance” which satisfied the definition of conduct to which Chapter II of Part I of RIPA applied (see para 74 of the determination; RIPA section 65(3)(d), (5)(c)). In some cases the jurisdiction of the IPT may overlap with that of the ordinary courts: see, for example, AKJ v Comr of Police of the Metropolis [2014] 1 WLR 285 (parallel claims under HRA section 7, and in tort, in respect of damage suffered as a result of the actions of two undercover police officers). 8. Section 67 is headed “Exercise of the Tribunal’s jurisdiction”. Subsection (1) provides that it shall be the duty of the Tribunal to hear and determine proceedings, or to consider and determine complaints or references, brought before it under section 65(2). Subsections (2) and (3) provide, among other things, that the tribunal shall apply “the same principles as would be applied by a court on an application for judicial review”. Subsections (4)-(6) make provision in relation to frivolous and vexatious claims, limitation, and the power to make interim orders. Subsection (7) sets out the powers of the tribunal “on determining any proceedings, complaint or reference” to make “any such award of compensation or other order as they think fit”. It also gives examples of such orders, including (a) “an order quashing or cancelling any warrant or authorisation”, and (b) “an order requiring the destruction of any records of information which (i) has been obtained in exercise of any power conferred by a warrant or authorisation; or (ii) is held by any public authority in relation to any person”. 9. Subsection (8) has been set out above (para 1). As there seen, it allowed for an appeal to be provided for by order of the Secretary of State, but that power has never been exercised. Subsection (9) goes further, imposing a “duty” on the Secretary of State to secure an order allowing for an appeal to a court against any exercise by the tribunal of their jurisdiction under section 65(2)(c) or (d); but that Page 6 subsection has not been brought into force. Subsections (10)-(12) make provision as to the contents of, and procedure for making, such an order were the power ever to be exercised. After the commencement of these proceedings there was enacted (by section 242 of the Investigatory Powers Act 2016) a new section 67A providing for an appeal on a point of law to the Court of Appeal or Court of Sessions against certain decisions of the tribunal. That was brought into force on 31 December 2018 by regulation 2 of the Investigatory Powers Act 2016 (Commencement No 10 and Transitional Provision) Regulations 2018/1397, but it does not apply to any decision or determination of the IPT made before this date. It is therefore not material to the present appeal. 10. Until 31 December 2018, when they were replaced by the Investigatory Powers Tribunal Rules 2018 (SI 2018/1334), the procedure before the IPT was governed by the Investigatory Powers Tribunal Rules 2000 (SI 2000/2665) (made under section 69(1)). Notable are the power to conduct proceedings in private and at certain stages in the absence of the complaining party (rule 9), and the duty under rule 6(1): “The Tribunal shall carry out their functions in such a way as to secure that information is not disclosed to an extent, or in a manner, that is contrary to the public interest or prejudicial to national security, the prevention or detection of serious crime, the economic well-being of the United Kingdom or the continued discharge of the functions of any of the intelligence services.” The European Court of Human Rights has held that the Act and the rules provide an effective and compliant remedy for complaints in respect of interception with communications, for the purposes of article 13 of the Convention (Kennedy v United Kingdom (2011) 52 EHRR 4). The proceedings below 11. The background of the present proceedings was described in the judgment of the IPT dated 12 February 2016. It was a hearing of preliminary issues of law, whose purpose was to establish: “whether, if the Second Respondent (‘GCHQ’) carries on the activity which is described as CNE (Computer Network Exploitation), which may have affected the claimants, it has been lawful.” Page 9 a statutory tribunal wholly immune from judicial oversight” was not engaged (paras 43, 45). 16. Leggatt J, while not formally dissenting, was “inclined” to a different view. He thought that the case was governed by the reasoning in Anisminic: “The only potentially relevant difference in the wording of section 67(8) is that it contains the words in brackets ‘(including as to whether they have jurisdiction)’. But I find it hard to see how these words can make a critical difference in the light of Anisminic. It seems to me that on a realistic interpretation that case did not decide that every time a tribunal makes an error of law the tribunal makes an error about the scope of its jurisdiction. Rather, it decided that any determination based on an error of law, whether going to the jurisdiction of the tribunal or not, was not a ‘determination’ within the meaning of the statutory provision. That reasoning, and the underlying presumption that Parliament does not intend to prevent review of a decision which is unlawful, is just as applicable in the present case and is not answered by pointing to the words in brackets.” (para 55) 17. The Court of Appeal gave judgment on 23 November 2017 dismissing the appeal. Sales LJ (with whom Floyd and Flaux LJJ agreed) considered that both the language and the context were materially different from Anisminic. As to the language he said: “… the drafter of section 67(8) has expressly adverted to the possibility of the IPT making an error of law going to its jurisdiction or power to act, by the words in parenthesis in that provision: ‘including decisions as to whether they have jurisdiction’. Therefore, at least so far as the word ‘decision’ is concerned, it is not tenable to apply the simple distinction relied upon in Anisminic in the context of section 4(4) of the 1950 Act between a ‘determination’ and a purported determination, in the sense of a determination made without jurisdiction. In section 67(8), the word ‘decision’ is stated to include a decision which (if judicial review or an appeal were available) might be found to have been made without jurisdiction because of an error of law on the part of the IPT - that is to say, if one wants to use this phrase, a purported decision.” (para 34) Page 10 18. In support of this view, he noted the “very high quality” of the IPT in terms of judicial expertise and independence (para 38), and the statutory context: “It is clear that Parliament’s intention in establishing the IPT and in laying down a framework for the special procedural rules which it should follow, including the Rules, was to set up a tribunal capable of considering claims and complaints against the intelligence services under closed conditions which provided complete assurance that there would not be disclosure of sensitive confidential information about their activities.” (para 42) 19. Finally he relied by analogy on the decisions of the Court of Appeal and Supreme Court in R (A) v Director of Establishments of the Security Service [2009] EWCA Civ 24; [2009] UKSC 12; [2010] 2 AC 1 (“R (A)”). It was held that section 65 of RIPA conferred on the IPT exclusive jurisdiction to hear claims under section 7 of the HRA against any of the intelligence services. In the Court of Appeal Dyson LJ noted that the rules were carefully drafted to achieve “a balance between fairness to a complainant and the need to safeguard the relevant security interests”; he thought it “inherently unlikely” that Parliament, having provided for such an elaborate set of rules to govern proceedings against an intelligence service, “yet contemplated that such proceedings might be brought before the courts without any rules” (para 48). That approach was approved in the Supreme Court. Although the effect of section 67(8) was not in issue, Lord Brown, giving the leading judgment, in the course of a review of this part of the Act, spoke of it as “an unambiguous ouster” of the court’s jurisdiction. 20. While accepting that this expression of view was obiter Sales LJ considered it to fit closely with Lord Brown’s analysis of the regime. He added: “Unless section 67(8) is interpreted as Lord Brown indicated, it would permit the special procedural regime established for the IPT to be bypassed at the stage when judicial review proceedings in respect of its decisions are brought in the High Court, as explained above. That would undermine the coherence of Lord Brown’s reasoning at para 14 of his judgment. In my view, Lord Brown’s view at para 23 about the proper interpretation and effect of section 67(8) is of powerful persuasive authority. I agree with it.” (para 48) Page 11 The submissions in this court 21. Two issues are identified in the agreed statement: i) whether section 67(8) of RIPA 2000 “ousts” the supervisory jurisdiction of the High Court to quash a judgment of the Investigatory Powers Tribunal for error of law? ii) whether, and, if so, in accordance with what principles, Parliament may by statute “oust” the supervisory jurisdiction of the High Court to quash the decision of an inferior court or tribunal of limited statutory jurisdiction? 22. On the first issue, counsel for the appellant led by Dinah Rose QC (with Professor Sir Jeffrey Jowell QC) rely principally on the long-established principle that a statute should not be interpreted as ousting judicial review of a statutory tribunal of limited jurisdiction if there is a tenable construction which would preserve the supervisory jurisdiction of the High Court. In the present case, the formula used in section 67(8) is not materially different from that which the House of Lords held not to oust judicial review in Anisminic, and must be taken to have the like effect. Lord Brown’s comment in R (A) was obiter, against the background of a concession by the appellant that judicial review was not available (R (A) at p 23D). 23. This did not mean that the reference in parenthesis to “jurisdiction” was without effect. Ms Rose refers for example to the distinction drawn in the cases depending on whether the legislature has or has not entrusted to the tribunal the power to determine the existence of “the preliminary state of facts” necessary to its jurisdiction (see R v Comrs for Special Purposes of the Income Tax (1888) 21 QBD 313, 319, per Lord Esher MR). At the time of the drafting of what became the 1985 Act, the difference between issues of fact and law in the context of jurisdiction had been highlighted by the House of Lords in R v Secretary of State for the Home Department, Ex p Khawaja [1984] AC 74. It was held that the power of the Home Office to remove an “illegal entrant” did not depend simply on the reasonable belief of the immigration officer that the person was an illegal entrant. As Lord Scarman said (at p 110): “… where the exercise of executive power depends upon the precedent establishment of an objective fact, the courts will decide whether the requirement has been satisfied.” Page 14 The King’s (or Queen’s) Bench 31. The supervisory role of the King’s court (curia regis), or the King’s or Queen’s Bench Division of the High Court as it became, has a long history. A scholarly account, tracing it back to the time of William I, is given in the judgment of Laws LJ in the Divisional Court in Cart ([2011] QB 120, paras 44ff). As he says (para 45) the King’s Bench was established by the end of the 13th century, and remained at the centre of the English judicial system until its powers were transferred to the High Court in 1873. 32. As to its status, he cites, for example (paras 48-49), Groenwelt v Burnell (1700) 1 Salk 144, 90 ER 1000 per Holt CJ: “… no court can be intended exempt from the superintendency of the King in this Court of King’s Bench. It is a consequence of every inferior jurisdiction of record, that their proceedings be removable into this court, to inspect the record, and see whether they keep themselves within the limits of their jurisdiction;” To similar effect he quotes Blackstone’s Commentaries on the Laws of England book III, Chapter 4, p 41-2 (written in 1768), describing the King’s Bench as “the supreme court of common law in the kingdom”, and as keeping “all inferior jurisdictions within the bounds of their authority”. It is of interest to note also a later passage (op cit p 112), in which Blackstone discussed the writ of prohibition, including its use to ensure general conformity with the law of the land. He described the wide variety of courts subject to this supervision (ranging from “inferior courts of common law”, to “the courts Christian or the university courts, the court of chivalry, or the court of admiralty”) and its application: “where they concern themselves with any matter not within their jurisdiction … or if in handling matters clearly within their cognizance they transgress the bounds prescribed to them by the laws of England … else the same question might be determined different ways, according to the court in which the suit is depending: an impropriety which no wise government can or ought to endure, and which is, therefore, a ground of prohibition.” 33. That supervisory role was preserved by section 16 of the Judicature Act 1873 which vested the common law powers of the Queen’s Bench in the newly created Page 15 High Court. Those powers were in turn preserved by section 19 of the Senior Courts Act 1981. Ouster clauses 34. Authorities dating back at least to the 17th century (see eg Smith, Lluellyn v Comrs of Sewers (1669) 1 Mod 44, 86 ER 719) leave no doubt as to the hostile attitude of the High Court to attempts by statute to restrict its supervisory role. In such cases, conventional principles of statutory interpretation, based on the ordinary meaning of the words used by Parliament, have yielded to a more fundamental principle that no inferior tribunal or authority can conclusively determine the limits of its own jurisdiction. 35. It is difficult, for example, to think of a statutory ouster clause in clearer terms than that considered in R v Cheltenham Comrs (1841) 1 QB 467, 113 ER 1211. The case concerned a challenge to a decision of the Quarter Sessions on an appeal against a rate set by the respondent Commissioners. The Commissioners’ objection to the admission of certain evidence had been rejected by a majority of 11 magistrates to eight. The decision was challenged on the grounds of apparent bias (in modern terms), in that three of the 11 magistrates were partners in a company which owned a property affected by the rate. The statute provided - “That no order, verdict, rate, assessment, judgment, conviction, or other proceeding touching or concerning any of the matters aforesaid, or touching or concerning any offence against this Act, or any by-law or order to be made in pursuance thereof, shall be quashed or vacated for want of form only, or be removed or removable by certiorari, or any other writ or process whatsoever, into any of His Majesty’s Courts of Record at Westminster; any law or statute to the contrary thereof in anywise notwithstanding.” Upholding the challenge, Lord Denman CJ said of the ouster clause: “… the clause which takes away the certiorari does not preclude our exercising a superintendence over the proceedings, so far as to see that what is done shall be in pursuance of the statute. The statute cannot affect our right and duty to see justice executed: and, here, I am clearly of opinion that justice has not been executed.” (p 1214) Page 16 36. A possible justification of that principle was given by Farwell LJ in R v Shoreditch Assessment Committee, Ex p Morgan [1910] 2 KB 859, 880: “Subjection ... to the High Court is a necessary and inseparable incident to all tribunals of limited jurisdiction; for the existence of the limit necessitates an authority to determine and enforce it: it is a contradiction in terms to create a tribunal with limited jurisdiction and unlimited power to determine such limit at its own will and pleasure - such a tribunal would be autocratic, not limited - and it is immaterial whether the decision of the inferior tribunal on the question of the existence or non- existence of its own jurisdiction is founded on law or fact …” (Emphasis added) This passage was cited with approval in Anisminic itself by both Lord Pearce ([1969] 2 AC 147, 197), and Lord Wilberforce (ibid pp 208-209), the latter describing it (perhaps somewhat grudgingly) as - “… language which, though perhaps vulnerable to logical analysis, has proved its value as guidance to the courts, …” He put the same idea in his own words: “The courts, when they decide that a ‘decision’ is a ‘nullity’, are not disregarding the preclusive clause. For, just as it is their duty to attribute autonomy of decision of action to the tribunal within the designated area, so, as the counterpart of this autonomy, they must ensure that the limits of that area which have been laid down are observed ... In each task they are carrying out the intention of the legislature, and it would be misdescription to state it in terms of a struggle between the courts and the executive. What would be the purpose of defining by statute the limit of a tribunal’s powers if, by means of a clause inserted in the instrument of definition, those limits could safely be passed?” (p 208B) 37. More recent authority has affirmed the continuing relevance of this strong interpretative presumption against the exclusion of judicial review, other than by “the most clear and explicit words” (Cart [2011] QB 120, para 31, per Laws LJ; citing Denning LJ in R v Medical Appeal Tribunal, Ex p Gilmore [1957] 1 QB 574, 583, and Lord Phillips MR in R (Sivasubramaniam) v Wandsworth County Court Page 19 That passage was concerned solely with the allocation of the special jurisdiction under the HRA, and against the background of clear Strasbourg authority that article 6 of the Convention does not guarantee a right of appeal (see Bochan v Ukraine (No 2) (2015) 61 EHRR 14, paras 44-45). It says nothing about the correct approach to the IPT’s jurisdiction more generally. From Anisminic to Cart Anisminic - the decision 41. The claim in Anisminic arose from the sequestration of the claimants’ property by the Egyptian authorities at the time of the Suez crisis in 1956. Their claim under the relevant Foreign Compensation Order (under the Foreign Compensation Act 1950) was rejected by the Commission on the grounds that they had subsequently sold their property to an Egyptian institution, which was to be regarded as their “successor in title” within the meaning of the Order. On its face, at least to modern eyes, that was a straightforward issue of interpretation of the Order. It was ultimately decided in the claimants’ favour by the House of Lords. 42. However, the process by which the case arrived at that point was far from straightforward. The procedural and legal background is described in an illuminating discussion of the case by Professor Feldman (Anisminic in perspective, in Juss and Sunkin (ed) Landmark cases in public law (Oxford 2017) pp 63ff). He explains in particular (p 70) the significance, in the absence of a reasoned decision by the Commission, of the choice of an action for a declaration, rather than certiorari: “Anisminic decided to challenge the provisional determinations in an action in the High Court seeking various declarations to the effect that they were erroneous in law and nullities. Unlike an application for certiorari, this did not require the court's leave, which would almost certainly have been refused because Anisminic was unable to point to any evidence that the Commission had erred in law. The action compelled the Commission to plead its defence, which eventually disclosed an error of law. There were disadvantages to Anisminic in pursuing a declaration rather than certiorari. First, there was no precedent for using a declaration as a remedy in such a case; the Commission argued that allowing declarations to be used in Page 20 that way might make certiorari redundant … Secondly, it forced Anisminic to argue that any unlawfulness the company could assert made the determination void, not merely voidable, as a voidable determination would be effective unless quashed by certiorari …” By the time the case came to the courts, as Lord Pearce noted (p 199F), the problem of showing an error of law “on the record” had been overtaken by the production by the Commission of a “minute of adjudication” relied in the particulars of the defence. 43. There were differences of emphasis between the various speeches in the House of Lords. However, for modern purposes they are less important than the interpretation of the decision in later cases. Looked at from that perspective, the case can be taken as confirming or establishing three distinct but related propositions: i) That there is (at the least) a strong presumption against statutory exclusion of review by the High Court of any decision of an inferior court or tribunal treated as made without jurisdiction and so a “nullity”. ii) That for this purpose there is no material distinction between an excess of jurisdiction at the outset, and one occurring in the course of proceedings. iii) That a decision which is vitiated by error of law (whether or not “on the face of the record”) is, or is to be treated as, made without jurisdiction and so a nullity. 44. The first proposition, as apparent from the cases referred to above, was little more than a confirmation of well-established principles. The second could be seen as a logical step forward, or at least a clarification of the previous law (see Wade & Forsyth Administrative Law 11th ed, p 217: “The ‘original jurisdiction’ fallacy”). 45. The third, however, was a much more radical development, in so far as a mere error of law came in due course to be treated as an excess of jurisdiction which rendered the decision not simply open to legal challenge but “void” or a “nullity”. Hitherto it had generally been assumed that a mere error of law by a court or tribunal in respect of an issue otherwise falling within its jurisdiction might be subject to correction on appeal, but did not take the decision outside its powers. For example, Lord Reid himself had said in a recent case: Page 21 “If a magistrate or any other tribunal has jurisdiction to enter on the inquiry and to decide a particular issue, and there is no irregularity in the procedure, he does not destroy his jurisdiction by reaching a wrong decision. If he has jurisdiction to go right he has jurisdiction to go wrong. Neither an error in fact nor an error in law will destroy his jurisdiction.” (R v Governor of Brixton Prison, Ex p Armah [1968] AC 192, 234 emphasis added) In Anisminic (at p 171E-F) he implicitly acknowledged an apparent discrepancy between that statement and the reasoning in instant case, which he sought to explain by reference to differences between narrow and broader meanings of the word “jurisdiction”. 46. Consideration of Lord Reid’s judgment is best begun by reference to his own summary of the respective arguments and his response to them (pp 169-170): “The respondent maintains that these are plain words only capable of having one meaning. Here is a determination which is apparently valid: there is nothing on the face of the document to cast any doubt on its validity. If it is a nullity, that could only be established by raising some kind of proceedings in court. But that would be calling the determination in question, and that is expressly prohibited by the statute. The appellants maintain that that is not the meaning of the words of this provision. They say that ‘determination’ means a real determination and does not include an apparent or purported determination which in the eyes of the law has no existence because it is a nullity. Or, putting it in another way, if you seek to show that a determination is a nullity you are not questioning the purported determination-you are maintaining that it does not exist as a determination. It is one thing to question a determination which does exist: it is quite another thing to say that there is nothing to be questioned.” Lord Reid considered the application of such an ouster provision to the “simple case” of an order made by someone appointed on the basis of a forged qualification, and asked whether the court would be required to treat the order as valid. He continued: Page 24 “If … the commission by misconstruing the Order in Council which gave them their jurisdiction and laid down the precise limit of their duty to inquire and determine, exceeded or departed from their mandate, their determination was without jurisdiction …” (p 201C) 50. Lord Wilberforce, who gave the only other substantive speech on this issue, also looked for something beyond a simple error of law. This was against the background that, as he put it: “In every case, whatever the character of a tribunal, however wide the range of questions remitted to it, however great the permissible margin of mistake, the essential point remains that the tribunal has a derived authority, derived, that is, from statute: at some point, and to be found from a consideration of the legislation, the field within which it operates is marked out and limited.”(p 207D) The error had to be one which took the tribunal outside its “permitted field”, leading to the decision being a “nullity” (a term which he thought “convenient … as a word of description rather than as in itself a touchstone”) and so outside the reach of the ouster clause (p 208A-B). In the instant case the statute had enabled the Order in Council to make provision for defining the persons qualified to make applications for the purpose of establishing claims and prescribing the matters to be established by them. Such definitions and prescribed matters, in his view, would be “architectural directions binding the commission”, departure from which would mean that it would be acting beyond its powers (p 211D-G). Having examined the Order in detail, and explained why, on a proper construction, all the relevant conditions had been satisfied, he concluded: “As … all these conditions were fulfilled to the satisfaction of the commission, the appellants’ claim was in law established; the commission by seeking to impose another condition, not warranted by the Order, was acting outside its remitted powers and made no determination of that which alone it could determine.” (p 214E) Anisminic - interpretation and comment 51. As Professor Feldman observes (op cit pp 92-93), the significance later attached to the decision in Anisminic, and in particular to the statement in Lord Page 25 Reid’s judgment of the matters leading to “nullity”, may not have been apparent at the time: “The ratio of the House of Lords decision was relatively narrow …, but what landmark cases decide and what they are later regarded as authority for may be very different.” Lord Reid’s statement had been “particularly influential” as the basis “for extending the theory and practice of judicial review well beyond anything justified by the ratio”. He also argues with some force that the passage reflects an uncharacteristic gap in logic: “Lord Reid leapt, apparently without noticing, from uncontroversial general propositions about circumstances in which certiorari would be available to quash a decision in the absence of any provision excluding the court’s jurisdiction, to a judgment about the effect of a very particular sort of error (denying eligibility for compensation for failing to comply with a condition which the legislation had not imposed) in a case where, because a declaration rather than certiorari was sought and, because of the effect of section 4(4) of the 1950 Act, it was essential to show that the challenged determination was not merely erroneous but null.” 52. Whatever doubts there may have been initially or since as to the interpretation or practical implications of Lord Reid’s words, and of the other majority speeches in Anisminic, such doubts have been dispelled by a series of statements in subsequent cases at the highest level, led by Lord Diplock. Professor Feldman (p 94) notes that at an early stage Lord Diplock’s own views of the case, as expressed extra-judicially, had progressed from a relatively cautious response in 1971 to a much more absolute view, as expressed in a 1974 lecture, that the decision had - “render(ed) obsolete the technical distinction between errors of law which go to ‘jurisdiction’ and errors of law which do not.” He also notes the influence of successive Junior Treasury Counsel in “set(ting) the tone for arguments advanced to the courts on behalf of Government Departments …” (see also para 80 below). Sir Stephen Sedley has spoken in similar terms of the contribution of Treasury Counsel, and of the process by which a consensus has emerged: Page 26 “It has come about … neither by legislation nor by precedent but by an organic process in which the law’s practitioners and its exponents have agreed on which way the common law should be travelling and have found a serviceable if not particularly suitable vehicle to transport it.” (Sedley “The lion behind the throne: the law as history” [2016] JR 289, paras 14, 22) 53. The problem is that this move outside the limitations carefully set by the Anisminic speeches may have undermined much of their conceptual basis. I shall return to this problem when addressing the second issue. O’Reilly v Mackman and after 54. It was not until 1982 that the broader view was given unambiguous judicial endorsement by the House of Lords, when Lord Diplock summarised the effect of Anisminic in O’Reilly v Mackman [1983] 2 AC 237, 279) in a speech agreed by the other members of the House: “The breakthrough that the Anisminic case made was the recognition by the majority of this House that if a tribunal whose jurisdiction was limited by statute or subordinate legislation mistook the law applicable to the facts as it had found them, it must have asked itself the wrong question, ie, one into which it was not empowered to inquire and so had no jurisdiction to determine. Its purported ‘determination’, not being a ‘determination’ within the meaning of the empowering legislation, was accordingly a nullity.” In other words, a determination arrived at on an erroneous view of the relevant law was not a “determination” within the meaning of an ouster clause such as in Anisminic. Arguments about differences between jurisdictional and non- jurisdictional errors of law had become redundant. 55. Later cases have confirmed this interpretation. Thus in R v Hull University Visitor, Ex p Page [1993] AC 682, concerning a challenge to the decision of a University Visitor, Lord Browne-Wilkinson said (at pp 701-702): “Anisminic … rendered obsolete the distinction between errors of law on the face of the record and other errors of law by extending the doctrine of ultra vires. Thenceforward it was to Page 29 exercised the authority of the monarch to keep the peace and uphold law and order. The prerogative writs together with inherent jurisdiction derived from their association with the monarch gave them wide discretionary powers. Those powers still play a role in claims for judicial review today. As a result of reforms in 1979, in addition to the prerogative orders being available to the judges of the new Court, the judges hearing cases on the ‘Crown Office List’ (the progenitor of the Administrative Court created in 2000) were also able to grant the declarations and injunctions which were the tools used by the judges of the Chancery Division when supervising the activities of public bodies. Declarations and injunctions, like the prerogative orders, were discretionary remedies. The powers to provide both sets of remedies meant that judicial review became a very effective method of upholding the rights of the individual against public bodies. This also meant that the technicalities relating to the grant of the prerogative remedies receded in importance.” 61. Anisminic also proceeded against the background of a reasonably clear division in the legal hierarchy between, on the one hand, the unlimited supervisory jurisdiction of the High Court, exercised by the Divisional Court usually presided over by the Lord Chief Justice, and, on the other, the limited jurisdictions of inferior courts or tribunals (or other adjudicative bodies, such as the Foreign Compensation Commission). For this purpose, no distinction was drawn in the authorities between the different forms of limited jurisdiction, or in particular between courts below the High Court and statutory tribunals. However, the period between Anisminic and the decision of the Supreme Court in Cart saw major changes in this traditional relationship between the High Court and other adjudicative bodies. Racal Communications 62. It is convenient at this point to refer to the decision of the House of Lords in In re Racal Communications Ltd [1981] AC 374 (“Racal”), to which Lord Sumption attaches some importance. As I understand it, he sees it and related cases as illustrating the proposition, which he derives from Lord Wilberforce’s speech in Anisminic (at p 207), that the key issue when considering the scope of an ouster clause is to define the “the permitted field” of the relevant adjudicative body, that being identified by a careful analysis of the interpretative power conferred by the enabling Act. Page 30 63. Racal itself concerned a challenge to the decision of a High Court judge exercising a statutory jurisdiction (under the Companies Act 1948 section 441) to authorise inspection by the Director of Public Prosecutions of company books for the purpose of investigating a suspected offence. Section 441(3) provided that the decision of the High Court judge on such an application “shall not be appealable”. The judge had dismissed an application by the Director on legal grounds, but the Court of Appeal had reversed his decision holding that it was entitled to do so because he had made an error of law which went to his jurisdiction. The House of Lords allowed the company’s appeal. 64. The case has attracted some attention for the distinction drawn by Lord Diplock in the context of ouster clauses between, on the one hand, “administrative tribunals and authorities” and, on the other, “courts of law”. Having confirmed that as respects the former the decision in Anisminic had effectively abolished “the old distinction between errors of law that went to jurisdiction and errors of law that did not”, he continued: “But there is no similar presumption that where a decision- making power is conferred by statute upon a court of law, Parliament did not intend to confer upon it power to decide questions of law as well as questions of fact. Whether it did or not and, in the case of inferior courts, what limits are imposed on the kinds of questions of law they are empowered to decide, depends upon the construction of the statute unencumbered by any such presumption …” (p 383) He went on to refer more specifically to the position of the High Court, as in the instant case. There was an obvious distinction between such a jurisdiction conferred by statute on a court of law of limited jurisdiction, and one conferred “on the High Court or a judge of the High Court acting in his judicial capacity”: “The High Court is not a court of limited jurisdiction and its constitutional role includes the interpretation of written laws. … Judicial review is available as a remedy for mistakes of law made by inferior courts and tribunals only. Mistakes of law made by judges of the High Court acting in their capacity as such can be corrected only by means of appeal to an appellate court; and if, as in the instant case, the statute provides that the judge’s decision shall not be appealable, they cannot be corrected at all.” (p 384) Page 31 65. As I see it, this distinction is of no assistance to the case of the Interested Parties, since there is nothing to suggest that Lord Diplock would have regarded the IPT, notwithstanding its distinguished composition, as anything more than an “administrative tribunal” within his classification. On that assumption Lord Diplock’s speech supports the widest reading of the Anisminic decision as later confirmed in O’Reilly v Mackman. In any event I do not see that part of his reasoning as having majority support. As I read the speeches overall, it was the latter point, turning on the position of the High Court, rather than of courts more generally, which provided the ratio of the House’s decision. Although Lord Keith agreed without qualification with Lord Diplock’s reasoning, his suggested distinction between courts in general and tribunals was not expressly endorsed by the other members of the House. Lord Edmund-Davies made no specific reference to this point. Lord Salmon spoke of the decision in Anisminic as confined to “decisions made by commissioners, tribunals or inferior courts”, drawing no distinction between them. He based his decision on the fact that the jurisdiction of the Court of Appeal was defined by statute, which gave it “no jurisdiction to make a judicial review of a decision of the High Court” (p 386). To similar effect, Lord Scarman (at p 393) relied on the fact that the Court of Appeal’s jurisdiction over the High Court was “the creature of statute”, and in no way analogous to the supervisory jurisdiction of the High Court over inferior tribunals. 66. Ms Rose goes as far as to submit that this part of the speech was “not only obiter but per incuriam”. There is force in this submission. As far as appears from the Appeal Cases report, the suggested distinction between courts and tribunals was not raised in argument and no relevant authorities were referred to in support, either by counsel or by Lord Diplock. His approach seems out of line with the long series of authorities cited by Laws LJ in his historical review in Cart, where it was emphasised that the jurisdiction of the King’s Bench Division extended to all inferior jurisdictions without distinction, including courts: a view well illustrated by Blackstone’s description of the range of courts within the scope of the writ of prohibition (paras 31-32 above). As Laws LJ said (commenting in terms on the speeches in Racal): “The true contrast is between the High Court of the one hand and courts of limited jurisdiction on the other …” (Cart [2010] 2 WLR 1012 at para 68) On this approach no principled distinction can be drawn between the Foreign Compensation Commission and the IPT, or indeed the Upper Tribunal in Cart. All were or are inferior jurisdictions, equally subject to the supervision of the High Court. Page 34 74. These references do not in my view materially assist the arguments in the present case on either side. All three cases (Pearlman, South East Asia and Racal) were products of their time. They came at a relatively early stage in the evaluation by the courts of the Anisminic principle. They also reflected a degree of tension between different levels of the judiciary as to the way forward. In this respect Lord Denning’s proposed interpretation seems closer to subsequent authority than that of the dissenting judgment, although his interpretation of the ouster clause seems more questionable, and the minority view might be supported on other grounds (discussed below, under the second issue). Specialist tribunals 75. By the time of Racal it was in any event difficult to make a principled distinction between courts and tribunals by reference only to nomenclature. Parliament had already blurred the distinction when establishing in 1975 the Employment Appeal Tribunal presided over by a High Court judge, with a jurisdiction limited to appeals on points of law (Employment Protection Act 1975 sections 87-88). It was designated in terms as “a superior court of record” (Schedule 6 paragraph 10). In this respect as in others it followed the precedent of the National Industrial Relations Court (Industrial Relations Act 1971 Schedule 3 paragraph 13). 76. As is apparent from the authorities cited by Laws LJ in Cart (paras 61-62) the accepted wisdom for many years, indeed until the decision of the Divisional Court in that case, was that such designation as a superior court of record was in itself sufficient to exclude judicial review by the High Court. He cites, for example, R v Regional Office of the Employment Tribunals (London North), Ex p Sojirin (unreported) 21 February 2000, in which Sedley LJ (with whom Brooke LJ and Sir Christopher Staughton agreed) stated: “So far as the Employment Appeal Tribunal is concerned, it is a superior court of record against which judicial review simply does not lie.” The same thinking was initially assumed to apply to the Upper Tribunal. Laws LJ cited De Smith Judicial Review 6th ed (2007), para 1-093: “The Administrative Court will have no role at all in relation to decisions of the Upper Tribunal, which as [a] superior court of record falls entirely outside the supervisory jurisdiction.” Page 35 Indeed, (as Lord Dyson noted in Cart in the Supreme Court - [2012] 1 AC 663 at para 117), Sir Andrew Leggatt in his report Tribunals for Users - One System, One Service (2001) (at para 6.31-34), had identified this as one possible means of excluding judicial review. This was not his preferred solution, principally because he saw it as “an artificial way of tackling the problem, which would blur the clear distinction we wish to achieve between the courts and the Tribunals System”. His preference was for exclusion of judicial review by express statutory provision. 77. It was not until Cart itself in the Divisional Court that this view of designation as a “superior court of record” was rejected as “a constitutional solecism”, when set against the principle that the supervisory jurisdiction of the High Court (if it can be ousted at all) can only be ousted “by the most clear and explicit words” (para 37 above). Laws LJ did however accept that the Upper Tribunal was “for relevant purposes, an alter ego of the High Court”, and that as such it: “… satisfies the material principle of the rule of law: it constitutes an authoritative, impartial and independent judicial source for the interpretation and application of the relevant statutory texts.” (para 94) 78. This led him to propose a limited form of judicial review not extending to a mere legal mistake by the tribunal “within the field ascribed to it”. As will be seen, this solution was not adopted by the Supreme Court. However, the proposition that designation as a superior court was sufficient in itself to exclude judicial review was not further pursued in this appeal. Laws LJ’s rejection of that proposition was accepted as correct by this court (see per Lady Hale para 30). I shall return to other passages in Laws LJ’s judgment in the context of the second issue in the appeal. Error of law and “nullity” in the modern law 79. The process of refinement of the Anisminic principle discussed above raised serious questions as to the need for continued reliance on concepts such as ultra vires or “nullity” as justifications for the intervention by the court. As Lord Reid himself had recognised (pp 170-171), the approach adopted in that case might be thought difficult to reconcile with a case such as Smith v East Elloe Rural District Council [1956] AC 736. That related to a statutory right within six weeks to challenge the confirmation of a compulsory purchase order on the grounds that it was “not empowered to be granted”, subject to which the order “shall not … be questioned in any legal proceedings whatsoever …”. It was held that the ouster clause was effective even where there was an allegation of fraud. In an often-cited passage, Lord Radcliffe (pp 769-770) commented on the argument that an order made in bad faith was a “nullity” and therefore incapable of having any effect: Page 36 “But this argument is in reality a play on the meaning of the word nullity. An order even if not made in good faith, is still an act capable of legal consequences. It bears no brand of invalidity upon its forehead. Unless the necessary proceedings are taken at law to establish the cause of invalidity and to get it quashed or otherwise upset, it will remain as effective for its ostensible purpose as the most impeccable of orders.” 80. In R v Secretary of State for the Environment, Ex p Ostler [1977] QB 122 the Court of Appeal held that it was bound by this decision; the availability of a statutory right to challenge within a specified time-limit, among other points, provided a sufficient basis for distinguishing Anisminic. This case also provides an interesting example of the influence of successive Junior Treasury Counsel in moulding the law (noted by Professor Feldman: above para 52 above). Lord Denning MR treated the statutory expression “not within the powers of this Act” as in effect embracing the familiar Wednesbury grounds, including error of law. This approach, following that of Lord Radcliffe (dissenting) in Smith v East Elloe Rural District Council, had been adopted by the Court of Appeal on the basis of a concession by counsel for the Minister (Nigel Bridge) in Ashbridge Investments Ltd v Minister of Housing and Local Government [1965] 1 WLR 1320; and in Ostler itself was not disputed by counsel for the Secretary of State (Harry Woolf). As Lord Denning said: “It has been repeatedly followed in this court ever since and never disputed by any Minister. So it is the accepted interpretation …” (p 133G-134A) The concession was no doubt well-advised, since without it there might have been difficulty in defending a time-limited right of challenge confined to excess of powers in the narrower sense. 81. On the relevance of the concept of “nullity” as used in Anisminic, Professor Paul Craig (op cit para 16-015) refers to the extra-judicial observations of Sir John Laws (Illegality: The Problem of Jurisdiction in Supperstone and Goudie Judicial Review 1st ed (1992)): “Sir John Laws argued that once the distinction between jurisdictional and non-jurisdictional errors was discarded, there was no longer any need for the ultra vires principle as such, since the courts were in reality intervening to correct errors of law. The rationale for the judicial persistence with the principle is that it provides a legitimating device for the exercise of the courts’ power. Sir John Laws captures this idea - Page 39 distinction for this purpose between different jurisdictions there gathered together; and thirdly that: “… the scope of judicial review is an artefact of the common law whose object is to maintain the rule of law - that is to ensure that, within the bounds of practical possibility, decisions are taken in accordance with the law, and in particular the law which Parliament has enacted, and not otherwise. Both tribunals and the courts are there to do Parliament’s bidding. But we all make mistakes. No-one is infallible …” Against the background the question as she saw it was - “… what machinery is necessary and proportionate to keep such mistakes to a minimum? In particular, should there be any jurisdiction in which mistakes of law are, either in theory or in practice, immune from scrutiny in the higher courts?” 89. Three possible approaches had been identified in the course of oral argument: “First, we could accept the view of the courts below in the Cart and MR (Pakistan) cases that the new system is such that the scope of judicial review should be restricted to pre-Anisminic excess of jurisdiction and the denial of fundamental justice (and possibly other exceptional circumstances such as those identified in the Sinclair Gardens case [2006] 3 All ER 650). Second, we could accept the argument, variously described in the courts below as elegant and attractive, that nothing has changed. Judicial review of refusals of leave to appeal from one tribunal tier to another has always been available and with salutary results for the systems of law in question. Third, we could adopt a course which is somewhere between those two options … namely that judicial review in these cases should be limited to the grounds upon which permission to make a second-tier appeal to the Court of Appeal would be granted.” (para 38) Page 40 Earlier in the judgment (para 27) she had recorded that the Lord Chancellor had exercised the power under section 13(6) to apply the “second-appeal” criteria as already applied in the Court of Appeal, to the effect that permission shall not be granted unless: “(a) the proposed appeal would raise some important point of principle or practice; or (b) there is some other compelling reason for the relevant appellate court to hear the appeal.” She considered the three options in turn. 90. The first (“the ‘exceptional circumstances’ approach”) would she thought lead back to the distinction between jurisdictional and other errors which had been effectively abandoned after Anisminic. She saw a number of other objections. In particular (echoing in some ways the concerns of Blackstone in the 18th century: para 32 above) she saw a risk of specialist tribunals, in contrast to the “ordinary courts”, developing their own “local law”, a risk which was increased by the power of the Upper Tribunal to set precedent “often in a highly technical and fast moving area of law”, combined with its ability to refuse permission to appeal, and the likelihood that “the same question of law will not reach the High Court or the Court of Appeal by a different route”: “There is therefore a real risk of the Upper Tribunal becoming in reality the final arbiter of the law, which is not what Parliament has provided. Serious questions of law might never be ‘channelled into the legal system’ (as Sedley LJ put it at [2011] QB 120, para 30) because there would be no independent means of spotting them. High Court judges may sit in the Upper Tribunal but they will certainly not be responsible for all the decisions on permission to appeal, nor is it possible for the Upper Tribunal to review its own refusals, even when satisfied that they are wrong in law.” (para 43) 91. In respect of the second (“The status quo ante - but which?”) she noted that the courts had already adopted principles of “judicial restraint” when considering decisions of expert tribunals. She referred (inter alia) to her own comments (Cooke v Secretary of State for Social Security [2001] EWCA Civ 734; [2002] 3 All ER 279, paras 15-17) on the need for “appropriate caution” in giving permission to appeal from the Social Security Commissioners because of their “particular expertise in a highly specialised area of the law”, but observed that other contexts (such as asylum) might require a different approach. The real question was: Page 41 “what level of independent scrutiny outside the tribunal structure is required by the rule of law … There must be a principled but proportionate approach.” (para 51) As to the third option (“The second-appeals criteria”), having noted the possible objections, she said: “But no system of decision-making is perfect or infallible. There is always the possibility that a judge at any level will get it wrong. Clearly there should always be the possibility that another judge can look at the case and check for error. That second judge should always be someone with more experience or expertise than the judge who first heard the case. … But it is not obvious that there should be a right to any particular number of further checks after that. The adoption of the second- tier appeal criteria would lead to a further check, outside the tribunal system, but not one which could be expected to succeed in the great majority of cases.” (para 56) 92. She concluded that the adoption of the second-tier appeals criteria would be a “a rational and proportionate restriction”, which would recognise that the new tribunal structure deserved: “a more restrained approach to judicial review than has previously been the case, while ensuring that important errors can still be corrected.” It was a test which the courts were now very used to applying, and one which was capable of encompassing: “both the important point of principle affecting large numbers of similar claims and the compelling reasons presented by the extremity of the consequences for the individual …” (para 57) 93. Of the other judgments I note that Lord Phillips (paras 91-92) was a relatively late convert to the need for even a restricted form of judicial review: “My initial inclination was to treat the new two-tier tribunal system as wholly self-sufficient. It is under the presidency of a judge who is likely to be a member of the Court of Appeal, and Page 44 Comment on Cart 98. I have referred at some length to the judgments in Cart because they represented a major reappraisal of the approach of the supervisory functions of the High Court as respects specialist tribunals. The case has attracted some academic controversy (see the discussion in Joanna Bell, “Rethinking the Story of Cart v Upper Tribunal and its implications for Administrative Law” Oxford Journal of Legal Studies Vol 39 No 1 (2019) pp 74-99). For example, Professor Forsyth describes the reasoning of the court as “pragmatic but not principled”, adding: “It may portend the abandonment of jurisdiction as the organising principle of administrative law and its replacement by the court allowing judicial review on discretionary basis when it is ‘rational and proportionate’ to do so (which would be a revolutionary change) …” (Wade & Forsyth, pp 222-223) 99. Certainly the judgments show how far the law has evolved since the somewhat technical debates in Anisminic itself. In particular, against the background of the Divisional Court judgment, they reaffirm in no uncertain terms the continuing strength of the fundamental presumption against ousting the supervisory role of the High Court over other adjudicative bodies, even those established by Parliament with apparently equivalent status and powers to those of the High Court. Instead such status (as adjudicative bodies rather than executive agencies) is to be respected and taken into account, not by exclusion of review, but by the careful regulation of the court’s power to grant or refuse permission for judicial review. Furthermore, setting the principles by which that is to be done, in the absence of specific statutory provision, is a matter properly within the province of the appellate courts. I shall return below, under the second issue, to the question in what circumstances if any Parliament could exclude review altogether. There is no doubt that, if it is to be done, nothing less than the clearest wording will suffice (see De Smith para 1-027). As has been seen, that principle has been a central theme of the authorities since well before Anisminic, and was reaffirmed in emphatic terms by the Divisional Court in Cart (para 37 above). 100. The principle can be seen as an application of the “principle of legality” as explained by Lord Hoffmann in R (Simms) v Secretary of State for the Home Department [2000] 2 AC 115 at p 131F: “the principle of legality means that Parliament must squarely confront what it is doing and accept the political cost.” Page 45 101. The practical importance of that principle was vividly illustrated by the fate of perhaps the most extreme form of ouster clause promoted by government in modern times: clause 11 of the Asylum and Immigration (Treatment of Claimants etc) Bill 2003. Not content with an express prohibition (in proposed clause 108A(1) and (2)) of any form of supervisory jurisdiction or questioning by the courts of tribunal decisions, the drafter had gone on to spell out precisely the intended consequence: “Subsections (1) and (2) - (a) prevent a court, in particular, from entertaining proceedings to determine whether a purported determination, decision or action of the Tribunal was a nullity by reason of - (i) lack of jurisdiction, (ii) irregularity, (iii) error of law, (iv) breach of natural justice, or (v) any other matter …” The clause attracted powerful objections from within and outside Parliament. The reaction of the Constitutional Affairs Committee was typical: “An ouster clause as extensive as the one suggested in the Bill is without precedent. As a matter of constitutional principle some form of higher judicial oversight of lower Tribunals and executive decisions should be retained.” (Second Report of the 2003-2004 Session para 708) In response to this pressure the clause was withdrawn. Page 46 Other common law jurisdictions 102. For completeness I should make clear that I have not overlooked the many authorities to which we have been helpfully referred from other common law jurisdictions, where similar issues have been discussed at the highest level, not always with the same results. All these decisions need to be read within the differing legal and constitutional arrangements of the jurisdictions concerned. For that reason, and without disrespect to the depth of learning and analysis there shown, I have not been persuaded that they add materially to the assistance available in the present context from the relevant domestic authorities and textbooks. 103. For example, the High Court of Australia has arrived at similar results by a broadened concept of jurisdiction (see Boughey and Burton Crawford “Reconsidering [Cart] and the rationale for jurisdictional error” [2017] Public Law 1). Thus, in Kirk v Industrial Court of New South Wales [2010] HCA 1, the court held that an ouster clause expressed in apparently far-reaching terms was ineffective to exclude review in relation to a particular error of law held to be “jurisdictional”. The court took an expansive view of the concept of “jurisdiction”, quoting the opinion expressed in an article by Professor Jaffé (“Judicial Review: Constitutional and Jurisdictional Fact” (1957) 70 Harvard Law Review pp 953, 963): “… that denominating some questions as ‘jurisdictional’ is almost entirely functional: it is used to validate review when review is felt to be necessary. … If it is understood that the word ‘jurisdiction’ is not a metaphysical absolute but simply expresses the gravity of the error, it would seem that this is a concept for which we must have a word and for which use of the hallowed word is justified.” The court noted the line of House of Lords authorities under which the difficulties had been overcome by holding that any error of law by a decision-maker rendered the decision ultra vires, commenting: “But that is a step which this court has not taken” (para 64). More generally the court observed that there can be “no automatic transposition” of principles from one jurisdiction to the other because “the constitutional context is too different” (para 66). The present appeal - the first issue 104. Against that background I can state my conclusions on the first issue relatively briefly. I remind myself of the terms of section 67(8): Page 49 not use more explicit wording. With O’Reilly v Mackman in mind, the natural focus of attention would have been, not on potential challenges to the tribunal’s own decisions “as to” jurisdiction, but on jurisdictional or legal challenges to its substantive decisions generally. A more explicit formula might perhaps have anticipated the extreme wording of the bill presented in 2003 (para 101 above), excluding challenges to any determination or “purported” determination as “a nullity by reason of lack of jurisdiction, error of law, or any other matter”. The reason for not adopting that course may simply be that, as in 2003, it might not have been expected to survive Parliamentary scrutiny. 112. So far as concerns the features of the IPT regime on which the Court of Appeal relied, I agree generally with Ms Rose’s responses (paras 24-25 above). I am unimpressed by arguments based on the security issues involved in many (though not all) of the IPT’s cases. As this case shows, the tribunal itself is able to organise its procedures to ensure that a material point of law can be considered separately without threatening any security interests. The Administrative Court can also ensure that the grant of permission is limited to cases raising points of general significance, and that its proceedings are conducted without risk to security concerns. Further, in the case of the IPT, the potential for overlap with legal issues which may be considered by the ordinary courts (see paras 7 and 14 above) makes it all the more important that it is not able to develop its own “local” law without scope for further review. The second issue 113. The second issue poses the question - “whether, and, if so, in accordance with what principles, Parliament may by statute ‘oust’ the supervisory jurisdiction of the High Court to quash the decision of an inferior court or tribunal of limited statutory jurisdiction?” The conclusion I have reached on the first issue makes it strictly unnecessary to go further in this appeal. However, as is apparent from the submissions under the second issue, the principles discussed in this judgment have important implications beyond the form of ouster clause under consideration in this case, on which some comment may be of value. 114. The essence of Ms Rose’s submission can be simply stated. It is in short that a clause purporting to “oust” the supervisory role of the High Court to correct errors of law cannot properly be upheld because it would conflict with the “rule of law”, a Page 50 principle which is as fundamental to our constitution as the principle of Parliamentary sovereignty. She emphasises that she does not in this appeal seek to question the principle of Parliamentary sovereignty itself, but rather - “to explain its boundaries, and why the laws of a sovereign Parliament require an independent interpreter of unlimited jurisdiction to ensure those laws are faithfully implemented.” That independent arbiter must she says be a court of unlimited jurisdiction, such as the High Court in England and Wales, or the Court of Session in Scotland; and its decisions must in turn be capable of correction by the appellate courts. 115. For the interested parties, Sir James Eadie does not question the need for an independent, authoritative interpreter of legislation, as “a fundamental requirement of the rule of law” (in his words); but he submits that the High Court is not the only body capable of performing that function. The IPT is of equivalent judicial status. Nor is there any absolute constitutional requirement for a right of appeal to the higher courts (see per Lord Brown in R (A), para 24). The balance between the correction of judicial error and the policy considerations in favour of finality is a judgement properly for the legislature. 116. Both parties find support in the judgment of Laws LJ in Cart [2011] QB 120, paras 36-40 (a passage cited with approval by Lady Hale in the Supreme Court: [2012] 1 AC 663, para 30). Ms Rose relies on his affirmation of the need under the rule of law for statute law to be “mediated by an authoritative source”, the “paradigm” being the High Court as “the principal constitutional guardian of the rule of law …”, and further that - “… the need for such an authoritative judicial source cannot be dispensed with by Parliament. This is not a denial of legislative sovereignty, but an affirmation of it …” (para 38) 117. On the other side, Sir James relies on Laws LJ’s acceptance in Cart that Parliament could entrust that supervisory role to a body properly regarded as the “alter ego” of the High Court, such as in that case the Upper Tribunal (paras 39, 94). He also relies on Laws LJ’s acknowledgment in the same passage (at para 40) of Parliament’s power to “modify, sometimes radically the procedures by which statute law is mediated”; exemplified by the many cases in which Parliament has, without objection, replaced the High Court’s common law powers with time-limited statutory powers of review (as seen in Ex p Ostler: para 80 above). Thus, he says, there is no constitutional principle to preclude such legislative choices about which Page 51 such judicial body is to have the power to make final decisions, and subject to what limitations. 118. As will be seen from these summaries, the area of disagreement even on the second issue is relatively narrow, but of considerable constitutional significance. It is useful to start by identifying those matters which appear not presently to be in dispute. 119. First, both parties start from the premise that the relationship between Parliament and the courts is governed by accepted principles of the “rule of law”. Unsurprisingly, there is no challenge to the proposition (per Lord Dyson, quoted at para 96 above) that there is - “no principle more basic to our system of law than the maintenance of the rule of law itself and the constitutional protection afforded by judicial review.” We are not therefore concerned with the difficult constitutional issues which might arise if Parliament were to pass legislation purporting to abrogate or derogate from those accepted principles: see eg Jackson v Attorney General [2005] UKHL 56; [2006] 1 AC 262, para 102 per Lord Steyn; and the succinct but masterly discussion of the competing views, academic and judicial, by Lord Bingham in The Rule of Law (2010): Chapter 12 “The Rule of Law and the Sovereignty of Parliament”. 120. Further, as noted earlier in this judgment (para 33), Parliament itself has affirmed (most recently in the Senior Courts Act 1981) the long-established common law powers of the High Court, as a court of unlimited jurisdiction, including its role in keeping inferior courts and tribunals within the law. Equally important, though of more recent origin, is the express statutory recognition of the “rule of law” in section 1 of the Constitutional Reform Act 2005. That provides: “The rule of law This Act does not adversely affect - (a) the existing constitutional principle of the rule of law …” Page 54 making determinations on claims or complaints made to it. There is nothing implausible about this. The quality of the membership of the IPT in terms of judicial expertise and independence is very high, as set out in Schedule 3 to RIPA, so it is a fair inference that Parliament did intend that this should be the position.” (paras 37-38) Sir James Eadie cited this passage as an illustration of the court’s proper function of interpreting such ouster provisions with regard to their statutory context. 125. I do not read this passage as suggesting that the residual jurisdiction in respect of the rules of natural justice would be wholly excluded, however gross the breach. Nor did I understand Sir James to go so far. There are useful parallels with Laws LJ’s discussion (Cart, paras 96ff) of the “exceptional circumstances” in which a county court judgment may be reviewable, under the principles established in R (Sivasubramaniam) v Wandsworth County Court [2002] EWCA Civ 1738; [2003] 1 WLR 475. As Laws LJ said, complaints of unfairness in the course of a hearing are “legion, and very various”, and need to be approached with caution. Citing an earlier judgment of his own (R (Strickson) v Preston County Court [2007] EWCA Civ 1132, para 32) he drew a distinction between a case where the judge “simply gets it wrong” and one where the judicial process itself has been “frustrated or corrupted”, including “substantial denial of the right to a fair hearing” or in other words “a wholly exceptional collapse of fair procedure: something as gross as actual bias on the part of the tribunal”. 126. In the Court of Appeal in the present case there appears to have been no reference to this part of Laws LJ’s judgment, nor to the kind of cases that he was discussing. However, I would be surprised if Sales LJ, even on his interpretation of section 67(8), would have treated it as excluding altogether the possibility of review in such extreme cases, however unlikely they might be in a tribunal of the distinction of the IPT. In accordance with established principles, the ultimate safeguard of judicial review remains essential if the rule of law is to be maintained. The special status of the IPT (like that of the Upper Tribunal) may be a reason for restricting the grant of permission for judicial review, but not for excluding it altogether. 127. I turn to the area of dispute in the present appeal. We are concerned, not with excess or abuse of jurisdiction in any of the senses discussed above, but with a straightforward question of legal interpretation on a point directly within the apparent scope of the IPT’s statutory remit. There is no disagreement as to the need for independent judicial interpretation of such a question. The dispute is as to the power of the legislature, consistently with the rule of law, to entrust that task to a judicial body such as the IPT, free from any possibility of review by the ordinary courts (including the appellate courts). Page 55 128. In that respect in my view the discussion needs to move beyond the legal framework established by Anisminic, and the cases which followed it. Those decisions established the principle that, if a tribunal goes wrong on any such question of law, it exceeds its jurisdiction, so that the resulting decision is a “nullity”, and (subject to an effective ouster clause) liable to be so declared by the High Court. Although this principle is now unquestioned, its conceptual basis, 35 years on from O’Reilly v Mackman, remains obscure. Anisminic itself does not assist. As has been seen (paras 48-50), the majority judgments did not go as far as to treat simple mistake of law as a cause of nullity. For Lord Reid the mistake must have been such as to lead the tribunal to “(fail) to deal with the question remitted to it, or to (decide) some question which was not remitted to it”. For Lord Wilberforce the mistake must have related to the “architecture” of the provisions. They were both able, after elaborate analysis, to find that the Commission’s mistake of law satisfied these tests. Whether the same could be said of the alleged error in the present case is at best doubtful. 129. As already observed, the “nullity” analysis seems highly artificial, as applied to a legal decision such as that of the IPT in this case. It is also difficult to reconcile with the acceptance by the courts of the familiar statutory ouster of challenges to planning and similar decisions after a six-week time-limit (as in Smith v East Elloe, and Ostler: see para 81 above), leading to the anomaly that such a “nullity” is mysteriously validated at the end of that period. Nor has the expanded understanding of the Anisminic principle been consistently applied in other statutory contexts, as In re McC [1985] AC 528 illustrates (para 58 above). 130. These examples show that the courts have not adopted a uniform approach, but have felt free to adapt or limit the scope and form of judicial review, so as to ensure respect on the one hand for the particular statutory context and the inferred intention of the legislature, and on the other for the fundamental principles of the rule of law, and to find an appropriate balance between the two. Even if this was not always the way in which the decisions were justified at the time, it may be seen as providing a sounder conceptual basis. Thus in the planning cases, it having been accepted that the statutory grounds cover all the traditional ground of judicial review, there is no difficulty in holding that the six-week time-limit provides a proportionate balance between effective judicial review, and the need for certainty to enable such decisions to be acted on with confidence. 131. That more flexible approach to the relationship between the legislature and the courts is in my view wholly consistent with the modern constitutional settlement, as confirmed by the 2005 Act, and recognised by this court in Miller. Against that background, the judgments of this court in Cart point the way to an approach which (pace Professor Forsyth - see para 98 above) is both pragmatic and principled. The critical step taken by this court in Cart was to confirm, what was perhaps implicit in Page 56 some of the earlier cases, that it is ultimately for the courts, not the legislature, to determine the limits set by the rule of law to the power to exclude review. 132. This proposition should be seen as based, not on such elusive concepts as jurisdiction (wide or narrow), ultra vires, or nullity, but rather as a natural application of the constitutional principle of the rule of law (as affirmed by section 1 of the 2005 Act), and as an essential counterpart to the power of Parliament to make law. The constitutional roles both of Parliament, as the maker of the law, and of the High Court, and ultimately of the appellate courts, as the guardians and interpreters of that law, are thus respected. The question in any case is “the level of scrutiny required by the rule of law”, set on a basis which as stated in Cart is both “principled and proportionate” (para 51 per Lady Hale), or in Lord Dyson’s words (para 133): “what scope of judicial review … is required to maintain the rule of law”; it being “a matter for the courts to determine what that scrutiny should be” (para 102 per Lord Clarke). 133. Some forms of ouster clause may readily satisfy such a test, as in the planning cases mentioned above. Similarly, in Racal, review limited to a High Court judge could reasonably have been justified as providing a sufficient and proportionate level of protection in the narrow statutory context of the grant of authority to inspect company books. 134. In a different context a similarly balanced assessment could be used to support the outcome of the dissenting judgment in Pearlman. Here again judicial thinking has moved on, recognising that the division between fact and law is not always clear-cut, and that a more “pragmatic” approach may sometimes be required (per Lord Hope, Jones v First-tier Tribunal [2013] UKSC 19, para 16). The assessment of whether particular works involve a “structural alteration … or addition” is substantially a factual issue, which can properly and economically be left to the trial judge at County Court level. An ouster provision designed to achieve that effect should be respected. On the other hand such a clause should not be treated as excluding the possibility of review in an exceptional case where the judge can be shown (in Geoffrey Lane LJ’s words) to have been “embarking on some unauthorised or extraneous or irrelevant exercise”. It is significant that this judgment (later approved by the Privy Council), like that of the Court of Appeal in Sivasubramaniam (para 125 above), implicitly recognised that even in a very restrictive statutory context the possibility of judicial review could not be excluded altogether in an exceptional case. 135. Lord Sumption finds support for his contrary view in a part of Lady Hale’s judgment in Cart, where she said: Page 59 could not be corrected at all (see para 64 above). In R (A) Lord Brown accepted as correct the concession that “there is no constitutional (or article 6) requirement for any right of appeal from an appropriate tribunal” (para 23). 142. As applied to article 6 of the Convention, which was in issue in R (A), that proposition may be uncontroversial, given that the ultimate arbiter of Convention law is in Strasbourg rather than the courts of this country. In the context of a domestic law challenge, it is more debatable. Arguably, following the logic of the reasoning in Cart, it may be thought implicit in the constitutional framework for the rule of law, as established by the Senior Courts Act 1981 and the Constitutional Reform Act 2005, that legal issues of general importance should be reviewable by the appellate courts; and that an ouster clause which purports to exclude that possibility cannot, consistently with the rule of law, be upheld. The only authority referred to by Lord Brown was Farley v Secretary of State for Work and Pensions (No 2) [2006] 1 WLR 1817. That case was concerned with a provision that, on an application by the Secretary of State to the magistrates’ court to enforce a “maintenance assessment”, the assessment itself was immune from challenge. The effectiveness of that ouster was upheld, but that depended on it being shown that there was another suitable means of challenging the assessment. 143. The issue does not arise directly in the present context. If the decisions of the IPT are in principle susceptible to judicial review by the High Court, there is nothing in RIPA or any other statute to exclude onward appeal from the decisions of the High Court itself in the ordinary way. We have not heard detailed argument on this aspect, and I decline therefore to express a concluded view. 144. In conclusion on the second issue, although it is not necessary to decide the point, I see a strong case for holding that, consistently with the rule of law, binding effect cannot be given to a clause which purports wholly to exclude the supervisory jurisdiction of the High Court to review a decision of an inferior court or tribunal, whether for excess or abuse of jurisdiction, or error of law. In all cases, regardless of the words used, it should remain ultimately a matter for the court to determine the extent to which such a clause should be upheld, having regard to its purpose and statutory context, and the nature and importance of the legal issue in question; and to determine the level of scrutiny required by the rule of law. Conclusion 145. Accordingly, for the reasons given under the first issue, I would allow the appeal and hold, in answer to the preliminary issue, that the judicial review jurisdiction of the High Court is not excluded by section 67(8). Although that is the limit of the issue before the court, it will be clear from what I have said about the Page 60 significance of the substantive legal issue, that this is a case where, if judicial review is available, permission should be granted. LORD LLOYD-JONES: 146. Two issues arise on this appeal. The first is the specific issue whether section 67(8) of the Regulation of Investigatory Powers Act 2000 (“RIPA 2000”) must be taken as purporting to oust the supervisory jurisdiction of the High Court to quash a judgment of the Investigatory Powers Tribunal (“the IPT”) for error of law. The second is the more general issue of whether, and, if so, in accordance with what principles, Parliament has the power by statute to oust the supervisory jurisdiction of the High Court to quash the decision of an inferior court or tribunal of limited statutory jurisdiction. 147. On the first issue, I agree with the judgment of Lord Carnwath. In view of the importance of the issue, I add some brief comments of my own. 148. The IPT was created by section 65(1) of RIPA 2000. Its jurisdiction and procedures are described in the judgment of Lord Carnwath and I simply draw attention to the following matters. Section 65(2) includes provision that it is the only appropriate tribunal for hearing proceedings falling within section 65(3) (which includes proceedings against any of the intelligence services) for actions incompatible with Convention rights under section 7 of the Human Rights Act 1998 (section 65(2)(a)). Section 67 provides that it shall be the duty of the Tribunal to hear and determine proceedings or to consider and determine complaints or references, brought before it under section 65(2). Section 67(2) provides that where the IPT hears any proceedings by virtue of section 65(2)(a), “they shall apply the same principles for making their determination in those proceedings as would be applied by a court on an application for judicial review”. At all material times the Investigatory Powers Tribunal Rules 2000 govern procedure before the IPT. It has the power to conduct proceedings in private and, in certain circumstances, in the absence of the complaining party. Rule 6(1) provides: “The Tribunal shall carry out their functions in such a way as to secure that information is not disclosed to an extent, or in a manner, that is contrary to the public interest or prejudicial to national security, the prevention or detection of serious crime, the economic well-being of the United Kingdom or the continued discharge of the functions of any of the intelligence services.” Page 61 149. Section 67(8) of RIPA 2000 provided at the relevant time: “Except to such extent as the Secretary of State may by order otherwise provide, determinations, awards and other decisions of the Tribunal (including decisions as to whether they have jurisdiction) shall not be subject to appeal or be liable to be questioned in any court.” An earlier version of this provision was section 7(8) of the Interception of Communications Act 1985 (“the 1985 Act”) which provided in relation to the Tribunal which it created and which was a predecessor of the IPT: “The decisions of the Tribunal (including any decisions as to their jurisdiction) shall not be subject to appeal or liable to be questioned in any court.” 150. Considered with the benefit of hindsight, it can be seen that Anisminic initiated a process of fundamental change in the approach of the courts to judicial review which was to lead to their abandoning the distinction between errors of law going to jurisdiction and those that did not. Whereas previously an error of law was reviewable only if it was a jurisdictional error or if it was an error on the face of the record, all errors of law were to become reviewable. However, as Professor Feldman has observed (“Anisminic Ltd v Foreign Compensation Commission [1968]: In Perspective”, in Juss and Sunkin (eds) Landmark Cases in Public Law (Oxford, 2017) pp 92-93), this was not immediately apparent from the speeches in Anisminic [1969] 2 AC 147 itself. On the contrary, they maintained the distinction between jurisdictional and non-jurisdictional errors of law and the decision turns on a particularly broad notion that the tribunal did not have the power to take certain decisions. Thus, for example, Lord Reid (at p 171B-F) distinguished between those errors of law or procedure by a tribunal which render a decision a nullity and other cases where “its decision is equally valid whether it is right or wrong subject only to the power of the court in certain circumstances to correct an error of law”. Similarly, Lord Wilberforce (at p 210D-E) considered that a “tribunal may quite properly validly enter upon its task and in the course of carrying it out may make a decision which is invalid - not merely erroneous” and referred to “a crucial distinction which the court has to make” between doing something which is not in the tribunal’s area and doing something wrong within that area. By addressing whether the appellants had a successor in title and its nationality, the Foreign Compensation Commission had asked the wrong question and had taken account of irrelevant considerations with the result that its decision was a nullity. Page 64 “But there is no similar presumption that where a decision- making power is conferred by statute upon a court of law, Parliament did not intend to confer upon it power to decide questions of law as well as questions of fact. Whether it did or not and, in the case of inferior courts, what limits are imposed on the kinds of questions of law they are empowered to decide, depends upon the construction of the statute unencumbered by any such presumption. In the case of inferior courts where the decision of the court is made final and conclusive by the statute, this may involve the survival of those subtle distinctions formerly drawn between errors of law which go to jurisdiction and errors of law which do not that did so much to confuse English administrative law before Anisminic …; but upon any application for judicial review of a decision of an inferior court in a matter which involves, as so many do, interrelated questions of law, fact and degree the superior court conducting the review should not be astute to hold that Parliament did not intend the inferior court to have jurisdiction to decide for itself the meaning of ordinary words used in the statute to define the question which it has to decide.” (at p 383E-G) In this way, Lord Diplock raised the possibility that the distinction between jurisdictional and non-jurisdictional errors of law may survive in the case of decisions by judicial bodies and that, in the latter case, they may be immune from judicial review. (It should be noted that the decision that judicial review was not available in Racal is also explicable on Lord Diplock’s alternative ground: because the body concerned was the High Court, not a court of limited jurisdiction, there was no room for error going to jurisdiction.) 156. The decision of the House of Lords in R v Hull University Visitor, Ex p Page lends support to the approach followed by Lord Diplock in Racal. On the other hand, however, it should be noted that Lord Diplock’s formulation of the Anisminic principle in O’Reilly v Mackman, two years after the decision in Racal, cited above, appears to be applicable without distinction to “inferior courts and statutory tribunals”. Furthermore, in R v Greater Manchester Coroner, Ex p Tal [1985] QB 67 Robert Goff LJ, delivering the judgment of the Divisional Court concluded (at p 81G-83B) that Lord Diplock in Racal had not intended to say that the Anisminic principle did not extend to inferior courts as well as tribunals. Goff LJ considered that, historically, inferior courts had always been subject to what was now called judicial review, although originally only in cases of error going to the jurisdiction and error of law within the jurisdiction which appeared on the face of the record: “Since Anisminic, the requirement that an error of law within the jurisdiction must appear on the face of the record is now Page 65 obsolete. It follows that today, in principle, inferior courts as well as tribunals are amenable to the supervisory jurisdiction of the High Court under sections 29 and 31 of the Supreme Court Act 1981.” (at p 82D-E) Referring to Lord Diplock’s statement of the law in O’Reilly v Mackman, he concluded that inferior courts as opposed to tribunals are not excluded from the Anisminic principle. 157. There is, moreover, no trace of such a distinction in the Supreme Court’s consideration of the Upper Tribunal in Cart where there is no suggestion that courts of limited jurisdiction might have power to err as to law within their jurisdiction. This leads Professor Forsyth to observe: “This suggests that all courts - except presumably the High Court as a court of unlimited jurisdiction - stray outside their jurisdiction when they make errors of law and are, in principle, subject to judicial review, save that the Supreme Court will determine, as it did in Cart, the actual extent of judicial review allowed.” (Wade and Forsyth, Administrative Law, 11th ed, (Oxford: 2014), p 223.) 158. The distinction between administrative tribunals and courts of law suggested by Lord Diplock in Racal is likely to be an arid one in the present context. Quite apart from the difficulties which are likely to be encountered in drawing such a distinction in individual cases, what matters here is whether a body is charged with performing a judicial function. If it is, then, as Laws LJ observed in the Divisional Court in Cart (at para 68), the true contrast is between the High Court on the one hand and courts of limited jurisdiction on the other. 159. In the present case the IPT is undoubtedly charged with performing a judicial function. The issue for decision in this case must therefore be approached on the basis that the statute makes provision as to the status of decisions of a judicial body. 160. I wholeheartedly endorse the exposition by Laws LJ in the Divisional Court in Cart (at paras 36-40) of the principle that it is a necessary corollary of the sovereignty of Parliament that there should exist an authoritative and independent body which can interpret and mediate legislation made by Parliament: “The interpreter’s role cannot be filled by the legislature or the executive: for in that case they or either of them would be judge Page 66 in their own cause, with the ills of arbitrary government which that would entail. Nor, generally can the interpreter be constituted by the public body which has to administer the relevant law: for in that case the decision-makers would write their own laws. The interpreter must be impartial, independent both of the legislature and of the persons affected by the texts’ application, and authoritative-accepted as the last word, subject only to any appeal. Only a court can fulfil the role.” (at para 37) He goes on to explain that this is not a denial of legislative sovereignty but an affirmation and a condition of it. The paradigm for such an authoritative source is the High Court but it is not the only possible source: “To offer the same guarantee of properly mediated law, any alternative source must amount to an alter ego of the High Court; …” (at para 39) and he identifies as examples the Courts-Martial Appeal Court and the Restrictive Practices Court. In the same way Parliament may modify the procedures by which statute law is mediated, inter alia by the creation of new judicial bodies. It seems to me that central to the first issue in the present appeal is whether it was the intention of Parliament to do precisely this in the case of the IPT. 161. I accept that in the case of a judicial body, by contrast with a purely administrative body, there is no presumption that Parliament did not intend to confer a power to decide questions of law as well as questions of fact. (See Racal per Lord Diplock at p 383E.) It is, rather, a matter of the interpretation of the legislation concerned in each case, unencumbered by such a presumption. Nevertheless, if the jurisdiction of the High Court is to be displaced or varied in some way, this is a matter of great importance and clear words will be required to achieve that result. Notwithstanding the disapproval by the House of Lords in Racal of the decision of the majority in the Court of Appeal in Pearlman, the following observation of Lord Denning MR (at p 70D) remains valid as a general proposition: “The High Court has, and should have, jurisdiction to control the proceedings of inferior courts and tribunals by way of judicial review. When they go wrong in law, the High Court should have power to put them right. Not only in the instant case to do justice to the complainant. But also so as to secure that all courts and tribunals, when faced with the same point of law should decide it in the same way.” Page 69 also in respect of purported determinations, awards and other decisions. It is a striking feature of section 67(8) and its predecessor that it failed to do so. 165. The one point of distinction between section 4(4) of the Foreign Compensation Act 1950, on the one hand, and section 67(8) on the other, is the inclusion in the latter of the words in parenthesis “(including decisions as to whether they have jurisdiction)”. To my mind, however, these words are not apt to extend the exclusion of the jurisdiction of the High Court to what purport to be decisions but in law are not to be so regarded. While it is now established that a decision based on an error of law is not to be regarded as a decision for this purpose, this notion does not easily fit within the description of a decision as to whether it has jurisdiction. If the IPT takes a decision which is founded on an error of law, it is not in any real sense taking a decision as to whether it has jurisdiction. If the intention was to exclude the jurisdiction of the High Court from purported decisions founded on an error of law, it was necessary to say so in clear terms. Clause 11 of the Asylum and Immigration (Treatment of Claimants etc) Bill 2003, to which Lord Carnwath refers at para 101 of his judgment, is a more recent example of an attempt to achieve the required degree of clarity if such a provision is to be effective. That provision, which was not enacted, can at least be said to have squarely confronted what it sought to achieve as required by the principle of legality. To my mind, section 67(8) does not satisfy this requirement. 166. It may be that the explanation of the words in parenthesis is, as submitted by Ms Dinah Rose QC on behalf of the appellant, that they were intended to refer to determinations of precedent fact, a matter which was highly topical in 1985 following the decision of the House of Lords in R v Secretary of State for the Home Department, Ex p Khawaja [1984] AC 74. On this basis the words in parenthesis in section 67(8) could be considered to have the effect that decisions of the IPT on issues of precedent fact going to its jurisdiction, but not issues of law, would be beyond the scope of review. However, it is not necessary to come to a concluded view on this point. For present purposes it is sufficient that the words employed in section 67(8) do not make provision with sufficient clarity for the exclusion of the review jurisdiction of the High Court in respect of errors of law. 167. In coming to this conclusion, I have taken full account of the various features of the statutory scheme to which Sir James Eadie QC has drawn attention in support of the respondents’ case. He is correct in his submission that there is here a special allocation of judicial responsibility to the IPT in the national security context (section 67(3)(a)). Similarly, the IPT’s rules and procedures create a “bespoke” system particularly well suited to the adjudication of controversial issues in the context of national security and directed to protecting the public interest. Furthermore, there can be no doubt as to the outstanding judicial quality of the members of the IPT. However, the exclusion of the review jurisdiction of the High Page 70 Court in cases of error of law, if achievable at all, would require a provision of much greater clarity making abundantly clear that that was what it sought to achieve. 168. For these reasons, I would allow the appeal against the decision of the Court of Appeal on the first issue. It is, accordingly, unnecessary to express any view on the second issue. LORD SUMPTION: (dissenting) (with whom Lord Reed agrees) 169. The Investigatory Powers Tribunal is a specialist tribunal established in 2000 under the Regulation of Investigatory Powers Act 2000. Its principal functions are to determine proceedings against the intelligence services in respect of breaches of human rights and complaints about the interception of communications, in a way which enables these claims to be examined judicially without the risk of disclosure of secret matters. The Tribunal effectively replaced the Interception of Communications Act Tribunal, the Security Services Act Tribunal and the Intelligence Services Act Tribunal, which had been established under earlier enactments, as well as taking over the operation of the complaints provisions of Part III of the Police Act 1997. 170. The appellant, Privacy International, complained that Government Communications Headquarters (“GCHQ”), one of the intelligence services, had carried out unlawful computer hacking. Computer hacking by the intelligence services requires the authority of a warrant of the Secretary of State under section 5 of the Intelligence Services Act 1994. The relevant activities of GCHQ were said to be unlawful on the ground that the warrants authorising them included what has been called (not entirely accurately) “thematic warrants”. A thematic warrant means a warrant authorising a class of activity in respect of a class of property. The appellant’s case before the Tribunal was that section 5(2) of the Intelligence Services Act 1994 empowered the Secretary of State to issue a warrant authorising “specified acts” in respect of “specified property”, and did not extend to thematic warrants. Alternatively, they submitted that if the Act did authorise such warrants, it was in that respect incompatible with articles 8 and 10 of the Human Rights Convention. The Tribunal held an open hearing to determine a number of preliminary issues of law. In a judgment issued on 12 February 2016, it held that thematic warrants were lawful. The appellant began proceedings for judicial review, seeking an order quashing that decision on the ground that the Tribunal’s construction of section 5(2) of the Act of 1994 was wrong in law. 171. Section 67(8) and (9) of the Regulation of Investigatory Powers Act 2000 provide: Page 71 “(8) Except to such extent as the Secretary of State may by order otherwise provide, determinations, awards, orders and other decisions of the Tribunal (including decisions as to whether they have jurisdiction) shall not be subject to appeal or be liable to be questioned in any court. (9) It shall be the duty of the Secretary of State to secure that there is at all times an order under subsection (8) in force allowing for an appeal to a court against any exercise by the Tribunal of their jurisdiction under section 65(2)(c) or (d).” The Secretary of State has not exercised his power to make exceptions from subsection (8) and the duty referred to in subsection (9) has not arisen because section 65(2)(c) and (d) has not been brought into force. The present position, therefore, is that subsection (8) stands unqualified. Section 242 of the Investigatory Powers Act 2016 has changed that by amending the Act of 2000 so as to introduce a new section 67A, allowing for appeals to the Court of Appeal in England and Wales or the Court of Session in Scotland. That section came into force on 31 December 2018, but will not apply to the Tribunal’s determination in these proceedings. 172. The question at issue on this appeal is whether an application for judicial review on the ground that the Tribunal has decided an issue on a wrong view of the law, is available having regard to section 67(8) of the Act. The Divisional Court and the Court of Appeal have both held that it is not. I agree with them. I shall need to examine the law in some detail, but my reason can be shortly summarised. The effect of section 67(8) is simply to exclude the jurisdiction of the High Court to entertain a challenge to the Tribunal’s decisions on the merits. In other words, it excludes judicial review on grounds which would be tantamount to an appeal. The Investigatory Powers Tribunal acts as a court. Its function is to exercise powers of judicial review over (among others) the intelligence services, which would otherwise have been exercisable by the High Court, and to do so on the same basis as the High Court. The purpose of judicial review is to maintain the rule of law. But the rule of law is sufficiently vindicated by the judicial character of the Tribunal. It does not require a right of appeal from the decisions of a judicial body of this kind. For this reason section 67(8) is not an ouster of any jurisdiction which constitutional principle requires the High Court to have. Ouster clauses: origins 173. Historically, the legal basis of judicial review was the concept of excess of jurisdiction. Bodies deriving their powers from statute or grant under the royal Page 74 exist as a determination,” unless the clause was framed in terms which were incapable of meaning anything else. Secondly, it established that a tribunal acts without jurisdiction not only where it lacks legal competence to enter upon the inquiry in question at all, but also where “although the tribunal had jurisdiction to enter upon the inquiry, it has done or failed to do something in the course of the inquiry which is of such a nature that its decision is a nullity”: per Lord Reid at p 171. Thirdly, the acts or omissions which served to make the decision a nullity include errors of law if they led the tribunal to conduct an enquiry which differed from the one that it was empowered to conduct, for example by making its decision dependent on the answer to a legally irrelevant question. This was what the Commission was found to have done in Anisminic’s case. It had dismissed Anisminic’s claim because it considered that those who claimed to have lost their property in Egypt as a result of acts of the Egyptian state during the Suez crisis had to show that not only they but their successors in title were British. Since Anisminic had been forced to sell their Egyptian assets at an undervalue to an Egyptian company, its claim had been rejected. In the view of the Appellate Committee, the status of successors in title was, on the true construction of the Order in Council, irrelevant. 177. Lord Reid, at p 171, gave some illustrations of errors on the part of the tribunal which, without going to legal competence in its strict sense, would nevertheless invalidate the decision: “It has sometimes been said that it is only where a tribunal acts without jurisdiction that its decision is a nullity. But in such cases the word ‘jurisdiction’ has been used in a very wide sense, and I have come to the conclusion that it is better not to use the term except in the narrow and original sense of the tribunal being entitled to enter on the inquiry in question. But there are many cases where, although the tribunal had jurisdiction to enter on the inquiry, it has done or failed to do something in the course of the inquiry which is of such a nature that its decision is a nullity. … It may have failed in the course of the inquiry to comply with the requirements of natural justice. It may in perfect good faith have misconstrued the provisions giving it power to act so that it failed to deal with the question remitted to it and decided some question which was not remitted to it. It may have refused to take into account something which it was required to take into account. Or it may have based its decision on some matter which, under the provisions setting it up, it had no right to take into account. I do not intend this list to be exhaustive. But if it decides a question remitted to it for decision without committing any of these errors it is as much entitled to decide that question Page 75 wrongly as it is to decide it rightly. I understand that some confusion has been caused by my having said in R v Governor of Brixton Prison, Ex p Armah [1968] AC 192, 234 that if a tribunal has jurisdiction to go right it has jurisdiction to go wrong. So it has, if one uses ‘jurisdiction’ in the narrow original sense. If it is entitled to enter on·the inquiry and does not do any of those things which I have mentioned in the course of the proceedings, then its decision is equally valid whether it is right or wrong subject only to the power of the court in certain circumstances to correct an error of law …” The question what had been remitted to the Commission by Parliament depended on the construction of its enabling Act and of Orders in Council made pursuant to it. So, turning to Anisminic’s complaint, Lord Reid concluded, at p 174: “If, on a true construction of the Order, a claimant who is an original owner does not have to prove anything about successors in title, then the commission made an inquiry which the Order did not empower them to make, and they based their decision on a matter which they had no right to take into account. If one uses the word ‘jurisdiction’ in its wider sense, they went beyond their jurisdiction in considering this matter. … It cannot be for the commission to determine the limits of its powers … if they reach a wrong conclusion as to the width of their powers, the court must be able to correct that - not because the tribunal has made an error of law, but because as a result of making an error of law they have dealt with and based their decision on a matter with which, on a true construction of their powers, they had no right to deal. If they base their decision on some matter which is not prescribed for their adjudication, they are doing something which they have no right to do and, if the view which I expressed earlier is right, their decision is a nullity.” 178. Lord Morris of Borth-y-Gest was at one with his colleagues on the test to be applied, although he dissented on its application to the facts. At p 182, he expressed it in this way: “In all cases similar to the present one it becomes necessary, therefore, to ascertain what was the question submitted for the determination of a tribunal. What were its terms of reference? What was its remit? What were the questions left to it or sent to it for its decision? What were the limits of its duties and Page 76 powers? Were there any conditions precedent which had to be satisfied before its functions began? If there were, was it or was it not left to the tribunal itself to decide whether or not the conditions precedent were satisfied? If Parliament has enacted that provided a certain situation exists then a tribunal may have certain powers, it is clear that the tribunal will not have those powers unless the situation exists. The decided cases illustrate the infinite variety of the situations which may exist and the variations of statutory wording which have called for consideration. Most of the cases depend, therefore, upon an examination of their own particular facts and of particular sets of words. It is, however, abundantly clear that questions of law as well as of fact can be remitted for the determination of a tribunal.” 179. Lord Pearce made the same distinction between errors of law which led the tribunal to address questions which it was not within their powers to determine, and other errors. At p 195, he observed: “Lack of jurisdiction may arise in various ways. There may be an absence of those formalities or things which are conditions precedent to the tribunal having any jurisdiction to embark on an inquiry. Or the tribunal may at the end make an order that it has no jurisdiction to make. Or in the intervening stage while engaged on a proper inquiry the tribunal may depart from the rules of natural justice; or it may ask itself the wrong questions; or it may take into account matters which it was not directed to take into account. Thereby it would step outside its jurisdiction. It would turn its inquiry into something not directed by Parliament and fail to make the inquiry which·Parliament did direct. Any of these things would cause its purported decision to be a nullity … The courts have, however, always been careful to distinguish their intervention whether on excess of jurisdiction or error of law from an appellate function. … If the tribunal is intended on a true construction of the Act to inquire into and finally decide questions within a certain area, the courts’ supervisory duty is to see that it makes the authorised inquiry according to natural justice and arrives at a decision whether right or wrong. They will intervene if the tribunal asks itself the wrong questions (that is, questions other than those which Parliament directed it to ask itself). But if it directs itself to the right inquiry, asking the right questions, they will not intervene merely because it Page 79 the kind of case I have mentioned there is no need to make this assumption. In another type of case it may be apparent that Parliament is itself directly and closely concerned with the definition and delimitation of certain matters of comparative detail and has marked by its language the intention that these shall accurately be observed.” Lord Wilberforce considered that the Commission’s error of law lay outside the “permitted field” assigned to it by Parliament. The reason, in summary, was that the Act in terms required the Commission to act in accordance with rules governing limitations laid down in the Order in Council regarding the definition of proper claimants and the matters to be established in support of their claims: see p 211F-H. 181. Implicit in the decision of the House in Anisminic was that invalidity for error of law no longer depended on the error being patent on the face of the record. But it will be apparent from all of the speeches that the Appellate Committee did not reject in principle the distinction between errors of law going to jurisdiction and errors of law within jurisdiction. Instead, they broadened the concept of jurisdiction to embrace not just legal competence but also legal relevance, ie addressing the right questions. All of them recognised that there would be some errors of law which did not go to jurisdiction even in this enlarged sense, and which would not therefore invalidate the decision. However, dicta of high authority in subsequent cases have consistently interpreted the decision as authority for an approach to errors of law which is both broader and more absolute than the speeches themselves warrant. In particular, they suggested that all errors of law were to be regarded as beyond jurisdiction. Thus in O’Reilly v Mackman [1983] 2 AC 237, 278, Lord Diplock regarded Anisminic as authority for the proposition that “if a tribunal whose jurisdiction was limited by statute or subordinate legislation mistook the law applicable to the facts as it had found them, it must have asked itself the wrong question, ie one into which it was not empowered to inquire and so had no jurisdiction to determine.” In R v Hull University Visitor, Ex p Page [1993] AC 682, 701-702, Lord Browne-Wilkinson, endorsing this summary, took it that thenceforth, “it was to be taken that Parliament had only conferred the decision-making power on the basis that it was to be exercised on the correct legal basis: a misdirection in law in making the decision therefore rendered the decision ultra vires.” In R (Lumba) v Secretary of State for the Home Department (JUSTICE intervening) [2012] 1 AC 245, para 66, Lord Dyson considered that it “established that there was a single category of errors of law, all of which rendered a decision ultra vires.” Finally, in R (Cart) v Upper Tribunal [2012] 1 AC 663, para 18, Baroness Hale observed that in Anisminic “the House of Lords effectively removed the distinction between error of law and excess of jurisdiction.” Although none of these statements were part of the ratio of judgments in which they appeared, they have been followed by the courts for many years and have been assumed to state the modern law by Parliamentary draftsmen including (as I shall show) the draftsman of the Regulation of Page 80 Investigatory Powers Act 2000. In my opinion, it is now too late to revert to the subtler distinctions in the speeches in Anisminic, even if it were thought desirable to do so. However, the speeches in Anisminic remain authority for the proposition, which may be thought self-evident, that the extent of a tribunal’s jurisdiction depends on the construction of its enabling Act or, in Lord Wilberforce’s words, on the breadth of its “permitted field”. Errors of law by judicial bodies 182. The categorisation of errors of law as excesses of jurisdiction is the result of the unsystematic way in which English public law has developed over the past three centuries. Its effect is to create what is nominally a power of review, but is in substance a right of appeal on points of law going to the merits. The implications of this are very different, according as the decision under review was made by an administrative or executive body on the one hand or a judicial one on the other. A right of access to a court or similar judicial body to review the lawfulness of administrative or executive acts is an essential part of the rule of law. But the rule of law does not require a right of appeal from such a body or a right to call for a review of its decisions. In England, appellate jurisdiction is wholly statutory, and may be absent, restricted or wholly excluded. This is well established as a matter of both law and legislative practice: see R (A) v Director of Establishments of the Security Service [2010] 2 AC 1, para 24 (Lord Brown of Eaton-under-Heywood). It has also been persistently recognised in the case-law of the European Court of Human Rights: see Bochan v Ukraine (No 2) (2015) 61 EHRR 14, paras 44-45. For this reason the development since Anisminic of a legal principle which made excesses of jurisdiction of all errors of law has been accompanied by a recognition that the reasons for strictly construing ouster clauses may be more or less powerful, depending on the nature of the decision and the decision-maker. In particular, the principle may have to be adapted to the decisions of judicial bodies. This is because a judicial body, depending on its status and functions, is more likely to have a wider “permitted field”, extending to the conclusive resolution of issues of law (or indeed fact) and including an unrestricted interpretative power. 183. The analysis starts with the speech of Lord Wilberforce in Anisminic itself, from which I have already quoted. Lord Wilberforce regarded the Foreign Compensation Commission as a body whose functions were “predominantly judicial” (p 207C), from which it followed that there was no reason to give a restricted interpretation to section 4(4) of the Foreign Compensation Act 1950. That, however, was not the end of the matter. In his view, the effectiveness of the ouster clause depended on the extent of the interpretatory power which, as a matter of construction, Parliament must be taken to have conferred on the decision-maker. Only errors of law lying outside what he called “the permitted field” were reviewable in the face of an ouster clause such as section 4(4): see pp 208A-B, 209F- G, 210C-E. As I have pointed out, Lord Wilberforce’s view that the Foreign Page 81 Compensation Commission’s error of law lay outside the “permitted field” was based on a careful analysis of the interpretative power conferred on it by its enabling Act, which was limited to applying the Order in Council according to its true legal meaning. 184. In South East Asia Fire Bricks Sdn Bhd v Non-Metallic Mineral Products Manufacturing Employees Union [1981] AC 363, the Privy Council had to consider whether the decision of the Industrial Court of Malaysia, a judicial body, could be reviewed in the High Court on the ground of error of law on the face of the record. The statute from which the Industrial Court derived its jurisdiction provided that its awards “shall be final and conclusive, and no award shall be challenged, appealed against, reviewed, quashed or called in question in any court of law.” The Board held the judicial review did not lie. Lord Fraser of Tullybelton, delivering the advice of the Privy Council, distinguished Anisminic, at p 370, on the ground that “if the inferior tribunal has merely made an error of law which does not affect its jurisdiction, and if its decision is not a nullity for some reason such as breach of the rules of natural justice, then the ouster will be effective.” The Board did not expressly address the distinction between judicial and other decision-makers, but since the judicial character of the Industrial Court was the only distinction between the case before them and Anisminic, that must have been the basis of the decision. Some light is thrown on this question by the speeches in In re Racal Communications [1981] AC 374, which addressed this very question, and were delivered a week later by an Appellate Committee comprising two of the same law lords, Lord Edmund-Davies and Lord Keith. 185. In re Racal Communications arose out of an application to the High Court under section 441 of the Companies Act 1948 to inspect the books of a company. Section 441(3) provided that the decision of the High Court on such an application “shall not be appealable”. The Court of Appeal had received the appeal on the ground that the ouster of its appellate jurisdiction was ineffective, relying on the decision in Anisminic. The House of Lords held that the Court of Appeal had been wrong to receive it in the face of the statutory exclusion of appeals. The leading speech was delivered by Lord Diplock. Having concluded that the House was bound by the statutory exclusion of appeals, he then turned to: “the question of the availability of judicial review instead of appeal as a means of correcting mistakes of law made by a court of law as distinct from an administrative tribunal or other administrative authority, however described, when it is exercising quasi-judicial functions.” It is important to appreciate that Lord Diplock gave two independent reasons for holding that judicial review was not available. The first and principal reason was Page 84 observations pertinent was that it was a judicial body. Almost all tribunals are obliged in some respects to act judicially, for example in acting fairly and without bias. But not all tribunals are judicial bodies. What matters is not the nomenclature of the decision-maker but its statutory functions. On an issue which is agreed on all sides to turn on the requirements of the rule of law, it would in my view be absurd to suggest that there is no distinction to be made between a statute providing for an administrative authority’s decisions to be conclusive and a statute making corresponding provision for the decisions of a judicial body. As I shall explain, the Investigatory Powers Tribunal is indistinguishable from a court in every respect that matters to the present issue. 188. More recently, in Lee v Ashers Baking Co Ltd [2018] 3 WLR 94, Racal was considered and applied by this court. The issue was whether a statutory provision making the decision of the Court of Appeal of Northern Ireland “final”, precluded a further appeal when the Court of Appeal had failed to refer a devolution issue to the Supreme Court as it had been bound to do. That question was answered by Lord Mance (with whom the rest of this court agreed). His judgment is relevant for two reasons. First, at para 86, he adopted Lord Diplock’s analysis, in particular his distinction between the presumptions to be applied to an ouster clause where the decision is that of a judicial body and those which apply where the decision is that of administrative tribunal. Secondly, he held that as a matter of construction the same language could in principle be sufficient to exclude an appeal on the merits but not an appeal on the ground that the court below had committed a procedural error or failed to perform the function with which Parliament had charged it. At para 88, he said: “The Court of Appeal in Northern Ireland is a superior court, but the underlying question of construction remains, whether the legislature has by article 61(7) of the 1980 Order, set out in para 63 above, excluded any right of appeal in circumstances such as the present. Article 61(1) and (7), read together, provide for the decision of the Court of Appeal on a case stated relating to the correctness of ‘the decision of a county court judge upon any point of law’ to be final. They contemplate the finality of the Court of Appeal’s decision with regard to the correctness of the county court judge’s decision on the point of law raised by the case stated. The finality provision in article 61(7) is therefore focused on the decision on the point of law, not on the regularity of the proceedings leading to it. It would require much clearer words - and they would, clearly, be unusual and surprising words - to conclude that a focused provision like article 61(7) was intended to exclude a challenge to the fairness or regularity of the process by which the Court of Appeal had reached its decision on the point of law. Suppose the Court of Page 85 Appeal had refused to hear one side, or the situation was one where some apparent bias affected one of its members. This sort of situation cannot have been contemplated by or fall within article 61(7).” R (Cart) v Upper Tribunal [2011] QB 120 and [2012] 1 AC 663 189. In view of the weight placed on this decision by the appellants, it is necessary to analyse the judgments with some care, although it must be borne in mind throughout that it is not direct authority on the question before us because it was not a case about ouster clauses. There was no ouster clause in the relevant statutes. 190. In the Divisional Court the issues were (i) whether the mere designation of a judicial body (in that case the Special Immigration Appeals Tribunal and the Upper Tribunal) as a superior court of record took it outside the scope of the High Court’s review jurisdiction even in the absence of an ouster; and (ii) whether the scheme of the statutes from which these bodies derived their powers was inconsistent with its decisions being reviewable in the High Court even in the absence of an ouster. In an impressive judgment, Laws LJ, delivering the judgment of the Divisional Court held that the answer to (i) was No and the answer to (ii) was Yes. On issue (i), he held that the special status of the High Court as exercising a jurisdiction to keep other bodies within their powers meant that a superior court of record other than the High Court was not, simply by virtue of that status, immune from the review jurisdiction of the High Court. For present purposes, however, what matters is Laws LJ’s treatment of issue (ii). He accepted that some courts and tribunals might be immune from the High Court’s review jurisdiction. He expressed the basic principle as follows: “37. The principle I have suggested has its genesis in the self- evident fact that legislation consists in texts. Often - and in every case of dispute or difficulty - the texts cannot speak for themselves. Unless their meaning is mediated to the public, they are only letters on a page. They have to be interpreted. The interpreter’s role cannot be filled by the legislature or the executive: for in that case they or either of them would be judge in their own cause, with the ills of arbitrary government which that would entail. Nor, generally, can the interpreter be constituted by the public body which has to administer the relevant law: for in that case the decision-makers would write their own laws. The interpreter must be impartial, independent both of the legislature and of the persons affected by the texts’ application, and authoritative - accepted as the last word, subject only to any appeal. Only a court can fulfil the role. Page 86 38. If the meaning of statutory text is not controlled by such a judicial authority, it would at length be degraded to nothing more than a matter of opinion. Its scope and content would become muddied and unclear. Public bodies would not, by means of the judicial review jurisdiction, be kept within the confines of their powers prescribed by statute. The very effectiveness of statute law, Parliament’s law, requires that none of these things happen. Accordingly, as it seems to me, the need for such an authoritative judicial source cannot be dispensed with by Parliament. This is not a denial of legislative sovereignty, but an affirmation of it: as is the old rule that Parliament cannot bind itself. The old rule means that successive Parliaments are always free to make what laws they choose; that is one condition of Parliament’s sovereignty. The requirement of an authoritative judicial source for the interpretation of law means that Parliament’s statutes are always effective; that is another. 39. As I have said, the paradigm for such an authoritative source is the High Court, which is independent of the legislature, the executive, and any other decision-makers acting under the law; and is the principal constitutional guardian of the rule of law. In section IV(2)(a) below I discuss the historic primacy of the High Court’s predecessor, the Court of King’s Bench. To offer the same guarantee of properly mediated law, any alternative source must amount to an alter ego of the High Court; and indeed there are instances where the authoritative source is another court, such as the Courts-Martial Appeal Court and the Restrictive Practices Court: see the reference, at para 71, below to R v Cripps, Ex p Muldoon [1984] QB 68. But the general principle is clear. The rule of law requires that statute should be mediated by an authoritative and independent judicial source; and Parliament’s sovereignty itself requires that it respect this rule.” Turning to the position of the SIAC and the Upper Tribunal, he observed: “78. The answer to these questions requires a closer look at what I have described as the overriding foundation for the grant of judicial review: an excess of jurisdiction by the subject court. This concept possesses (at least) two different meanings. The first denotes the case where a court travels into territory where it has no business. Thus a court whose jurisdiction is limited to claims of a pleaded value of £5,000 or less would exceed its Page 89 possibility of enforcement under its section 25 powers, it would be inimical to the rule of law if the High Court could not step in, should the appellate system for some reason not do so. Similarly if a member of the UT were to sit when ineligible or disqualified by a pecuniary interest, or if the UT conducted a hearing so unfairly as to render its decision a nullity, the High Court ought to be able to quash the determination. We do not mean this list to be exhaustive but to be illustrative of the kind of error, rare as it will be, which would take the UT outside the range of its decision-making authority. Such a division is, we consider, one of legal principle which can properly form the basis of judicial policy. It applies only to the UT, since it is the role of the UT itself to correct errors of every kind, including outright excesses of jurisdiction and fundamental denials of justice, in the FTT.” The Court of Appeal accepted that this might mean that the Upper Tribunal had “the potential to develop a legal culture which is not in all respects one of lawyers’ law.” 192. In the Supreme Court the sole issue was whether this implicit limitation on the scope of the jurisdiction to review decisions of the Upper Tribunal was justified. As Baroness Hale pointed out at para 37 (and again at paras 29 and 40), the starting point was that “there is nothing in the 2007 Act which purports to oust or exclude judicial review of the unappealable decisions of the Upper Tribunal. Clear words would be needed to do this and they are not there.” Any limitation therefore had to be implicit, as the Court of Appeal had held it was. The Supreme Court accepted that a restrained approach should be taken to the granting of leave, but rejected the Court of Appeal’s distinction between errors of law and “outright” excess of jurisdiction. It is important to appreciate that both the Court of Appeal and the Supreme Court regarded the question whether there was an implicit limitation of the scope of judicial review as a question of judicial policy. The difference between them was about what the relevant policy considerations were. In the Supreme Court’s view, the main policy consideration was the undesirability of allowing the Upper Tribunal to become (in Lady Hale’s words) the “final arbiter of the law”, in case inferior courts should undermine the coherence of the law by developing their own “local law” (para 43). This concern, which was mentioned by the Court of Appeal but had not troubled them, was central to the reasoning of this court. Nothing in this court’s analysis suggests that policy considerations of this kind would have been relevant, let alone decisive, if the issue had been the meaning and effect of an ouster clause. Nothing in the judgments promotes the undesirability of “local laws” from an interpretative presumption to a constitutional principle. The real significance for present purposes of this court’s decision in Cart lies in its recognition that the rule of law does not necessarily require that the decisions of an inferior tribunal be subject to a power of review, even where they are unappealable: Page 90 see in particular paras 89-90 (Lord Phillips of Worth Matravers), and paras 122-124 (Lord Dyson). Lord Dyson (with whom the rest of the court all agreed) referred to the status of the Upper Tribunal as a court performing functions equivalent to those of the High Court, and observed at para 122: “Prima facie, judicial review should be available to challenge the legality of decisions of public bodies. Authority is not needed (although much exists) to show that there is no principle more basic to our system of law than the maintenance of rule of law itself and the constitutional protection afforded by judicial review. But the scope of judicial review should be no more (as well as no less) than is proportionate and necessary for the maintaining of the rule of law. The status and functions of the Upper Tribunal to which I have already referred are important here.” The Investigatory Powers Tribunal 193. It follows from the modern authorities that the approach to be taken to section 67(8) of the Regulation of Investigatory Powers Act 2000 depends on the character of the Tribunal’s functions, the nature of the error of law of which it is accused by the appellant, and the construction of section 67(8) as applied to alleged errors of that kind. 194. The functions of the Investigatory Powers Tribunal are defined by section 65 of the Act. Section 65(2) is in the following terms: “(2) The jurisdiction of the Tribunal shall be - (a) to be the only appropriate tribunal for the purposes of section 7 of the Human Rights Act 1998 in relation to any proceedings under subsection (1)(a) of that section (proceedings for actions incompatible with Convention rights) which fall within subsection (3) of this section; (b) to consider and determine any complaints made to them which, in accordance with subsection (4) are complaints for which the Tribunal is the appropriate forum; Page 91 (c) to consider and determine any reference to them by any person that he has suffered detriment as a consequence of any prohibition or restriction, by virtue of section 17, on his relying in, or for the purposes of, any civil proceedings on any matter; and (d) to hear and determine any other such proceedings falling within subsection (3) as may be allocated to them in accordance with provision made by the Secretary of State by order.” The jurisdiction invoked by the present appellant is founded on sections 65(2)(a) and (b). Proceedings falling within subsection (2)(a) are, in summary, proceedings in respect of alleged contraventions of the Human Rights Convention against the intelligence services or those acting on their behalf, or against the authorities empowered to require the disclosure of electronic encryption keys. It also applies to the authorisation under statutory powers of what would otherwise be unlawful conduct by such bodies. The Tribunal has exclusive jurisdiction in respect of these proceedings and, under section 67(1)(a), a duty to “hear and determine” them. Complaints under subsection (2)(b) are, in summary, proceedings challenging the interception of communications by the intelligence services and other investigatory authorities, or warrants authorising such interception. Under section 67(1)(b), the Tribunal has a duty to “consider and determine” them, but its jurisdiction in respect of these complaints is not exclusive. 195. Section 67 regulates the manner in which the Tribunal’s jurisdiction is to be exercised. It provides, so far as relevant: “(2) Where the Tribunal hear any proceedings by virtue of section 65(2)(a), they shall apply the same principles for making their determination in those proceedings as would be applied by a court on an application for judicial review. (3) Where the Tribunal consider a complaint made to them by virtue of section 65(2)(b), it shall be the duty of the Tribunal - (a) to investigate whether the persons against whom any allegations are made in the complaint have engaged in relation to - Page 94 functions in the same judicial fashion as the High Court. It therefore satisfied the material principle of the rule of law: see para 94 of his judgment. The Court of Appeal and the Supreme Court regarded that as insufficient to warrant implying a limitation of the scope of judicial review, and nothing that I say is intended to undermine their view. But Laws LJ’s analysis is an illuminating explanation of the difference between an ouster of judicial review and a limitation of its scope to controlling the purported exercise of powers that the decision-maker did not have. That analysis is of considerable value in a case (unlike Cart) where an express statutory provision excludes judicial review of the legal merits of a tribunal’s decisions, without impinging on the High Court’s traditional jurisdiction to review “outright” excesses of jurisdiction. The next question, to which I now turn, is whether that is the effect of section 67(8) of the Regulation of Investigatory Powers Act. Section 67(8) 199. It is agreed on all sides that the meaning of this provision is a question of construction. It is also agreed that clear words are required if it is to be regarded as ousting the review jurisdiction of the High Court. However, we must not lose sight of the reason why clear words are required. The reason is, as all the authorities (and indeed Lord Carnwath in his judgment in the present case) agree, that Parliament is presumed not to legislate contrary to the rule of law. As Lord Hoffmann pointed out in R (Simms) v Secretary of State for the Home Department [2000] 2 AC 115, p 131, “that Parliament must squarely confront what it is doing and accept the political cost”. The degree of elaboration called for in a statutory provision designed to achieve a given effect must depend on how anomalous that effect would be. In this case, the words must be sufficiently clear to authorise a departure from the normal state of affairs, which is that the High Court has jurisdiction by way of review over the acts of lower courts. That is not the same as saying that the words must be such as to authorise a departure from the rule of law. There is nothing inconsistent with the rule of law about allocating a conclusive jurisdiction by way of review to a judicial body other than the High Court. The presumption against ouster clauses is concerned to protect the rule of law, which depends on the availability of judicial review. It is not concerned to protect the jurisdiction of the High Court in some putative turf war with other judicial bodies on whom Parliament has conferred an equivalent review jurisdiction. It was because Lord Brown found nothing constitutionally offensive in the allocation of specified disputes to the Investigatory Powers Tribunal that he had no difficulty in recognising in R (A) v Director of Establishments of the Security Service, supra, at para 23, that section 67(8) was “an ouster (and indeed unlike that in Anisminic, an unambiguous ouster) of any jurisdiction of the courts over the IPT.” This was no more than a dictum, on a point which was not argued. But in my opinion what Lord Brown said as a matter of impression was also correct as a matter of analysis, at any rate as applied to challenges to the Tribunal’s determinations on the merits. My reasons are as follows. Page 95 200. In the first place, the “jurisdiction of the Tribunal” defined in section 65(2) is to adjudicate on proceedings, complaints, references and on other matters allocated to them by the Secretary of State. By “adjudicate” I refer compendiously to the various expressions used in sections 65(2) and 67(1)-(3) to describe the Tribunal’s resolution of matters before it (“hear and determine”, “consider and determine”, “determine”, etc). The Tribunal’s “permitted field” (to use Lord Wilberforce’s phrase) plainly extended to determining questions of law arising in the course of any proceedings or complaint. In particular, it extended to determining the construction of the various enactments, such as the Intelligence Services Act 1994, under which the bodies subject to review by the Tribunal operated. There is nothing in the Act which lays down the test to be applied to any of these matters. Nor is there anything corresponding to the prescriptive regime in the Order in Council considered in Anisminic. The Act simply confers on the Tribunal the adjudicatory powers which would otherwise be exercised by the High Court acting as a court of review. 201. Secondly, turning to the language of section 67(8) itself, it is common ground that it falls to be construed against the background of the law declared in Anisminic and in subsequent decisions interpreting and applying it. The draftsman has deliberately chosen substantially the same formula as was considered in Anisminic (“shall not be … liable to be questioned in any court”). But it is clear that the draftsman did not intend the same result as in Anisminic. This is because he has modified the formula by adding the bracketed words “(including decisions as to whether they have jurisdiction)”. The effect of the bracketed words is to extend the ouster to the precise class of decisions which the House of Lords in that and subsequent cases had held not to be covered by the Anisminic formula, namely decisions in excess of jurisdiction. I do not, however, think that the intention was to extend it to all such decisions. The key lies in another addition to the Anisminic formula, namely the reference to an appeal. The Tribunal’s decisions “shall not be subject to appeal or be liable to be questioned in any court.” At common law, it was well established that the fact that a judicial decision was unappealable did not bar judicial review on all the usual grounds: see R (Cart) v Upper Tribunal [2012] 1 AC 663, paras 16-21 (Baroness Hale). In framing section 67(8) as it did, Parliament’s concern was plain. It was to ensure that the barring of appeals was not rendered nugatory by applications for judicial review on grounds which amounted to the same thing. Because the courts, in interpreting Anisminic, had categorised error, at any rate of law, as an excess of jurisdiction, this could be achieved only by extending the ouster clause so as to cover errors in the treatment of the merits notwithstanding that they were treated in Anisminic as an excess of jurisdiction. 202. Thirdly, it is true that a right to apply for judicial review is conceptually different from an appeal even if, in relation to an alleged error of law, they amount in practice to the same thing. But the concept of a judicial review by the High Court of a tribunal which is itself exercising a power of judicial review equivalent to that of the High Court, might be thought surprising. The rational course for Parliament Page 96 to have adopted, if it intended to allow judicial review on the ground of error, would have been to provide for an appeal. Parliament has in fact made such provision. But under section 67(9) it has done so unconditionally only in relation to cases falling within section 65(2)(c) and (d), which are not yet in force. In other cases, including those relevant to the present proceedings, the introduction of a right of appeal is left to the discretion of the Secretary of State under section 67(8). It would in my view be wrong in principle to construe the Act as allowing for judicial review on grounds indistinguishable from an appeal on the merits, when Parliament has so carefully circumscribed the conditions on which an appeal is available. 203. Fourthly, as Lord Wilberforce observed in Anisminic (p 209), conclusions about the Tribunal’s “permitted field” may be derived from the “form and subject- matter of the legislation”. The main subject-matter of this legislation is secret intelligence whose disclosure would be contrary to an obvious and powerful public interest. I have drawn attention above (at para 196) to the numerous indications to that effect in the Act. Its provisions, as Lord Brown of Eaton-under-Heywood pointed out in R (A) v Director of Establishments of the Security Service [2010] 2 AC 1, para 14, “are designed to ensure that, even in the most sensitive of intelligence cases, disputes can be properly determined.” The public interest engaged was pointed out in forceful terms by Sales LJ in his judgment in the Court of Appeal: see, in particular, para 7. It needs no further emphasis from me. There is accordingly an entirely rational reason, whose significance is apparent throughout the relevant parts of the Act, why Parliament should have wished to confine the examination of these matters to a secure Tribunal and to prevent resort to the High Court, whether by way of appeal or review. The whole object of the Act in creating the Tribunal was to make resort to the High Court unnecessary by providing an alternative but equivalent right of recourse to a judicial body performing the same function. It is right to add that section 68(4), which requires the Tribunal to give an unreasoned Yes or No answer to the questions before it, would make judicial review by the High Court exceptionally difficult in most cases. In future cases, governed by the Investigatory Powers Act 2016, there will be a right of appeal, in specified circumstances, and section 68(4) will be modified so as to be subject to the Tribunal Rules. Rules made under that Act allow for more extensive disclosure of the Tribunal’s reasons. But by the time that the 2016 Act was passed the position regarding the security of information deployed in forensic litigation had been transformed by the Justice and Security Act 2013, with its elaborate provisions for closed material procedure in civil proceedings in the High Court. The courts below regarded this as a decisive consideration. I think that there are a number of decisive considerations, but this is certainly one of them. 204. Finally one is bound to ask forensically, if section 67(8) when read as a whole does not exclude a challenge to the merits of the Tribunal’s decisions by way of judicial review, then what else can it mean? Ms Rose implicitly accepted that if it is to have any effect at all it must oust judicial review in relation to something. She