Kacper Majewski: Re Allister: The End of ‘Constitutional Statutes’?

On 8 February, the Supreme Court handed down its unanimous judgment in Re Allister [2023] UKSC 5. What follows is an attempt to clarify the judgment’s significance for the doctrine of constitutional statutes, as first canvassed by Laws LJ in Thoburn v Sunderland City Council [2002] EWHC 195 (Admin).

I think that the Court’s remarks in Re Allister can be read to show that there is no distinct doctrine of constitutional statutes in UK law. On one side, the Court seems to accept that the principle of legality—the interpretative presumption that Parliament does not wish to legislate against fundamental constitutional rights (R v Home Secretary, ex p Pierson [1998] AC 539R v Home Secretary, ex p Simms [2000] 2 AC 115)—can extend to such rights even when they are created by statute. On the other side, the judgment affirms Parliament’s ability to enact ‘subject to’ clauses to the effect that other enactments, including later Acts of Parliament, are to be read and given effect subject to some other rules. The cumulative effect is that there is little—if anything—left for the Thoburn doctrine to do. For all its academic interest, it is legally redundant.

The Issue of Constitutional Statutes in Re Allister

The relevant issue in Re Allister concerned the interaction between article VI of the 1800 Acts of Union and the European Union (Withdrawal) Act 2018, as amended by the European Union (Withdrawal Agreement) Act 2020 to give effect to the Brexit Withdrawal Agreement. Both parties accepted that there was a conflict between the Withdrawal Agreement and article VI; they disagreed on how the conflict should be resolved. The respondents maintained that section 7A(2) of the amended 2018 Act, which incorporated any directly applicable provisions of the Agreement into domestic law, suspended the application of article VI, in particular because of the provision in section 7A(3) that ‘every enactment … is to be read and has effect subject to subsection (2)’. The appellants insisted that the 1800 Acts of Union were constitutional statutes in the Thoburn sense. As a result, they argued, section 7A(3) could not affect the applicability of article VI without an express reference to it, or at least without words which would make ‘irresistible’ the conclusion that Parliament wished to qualify the article (that is, without passing the test put forward in paragraph [63] of Thoburn).

The Supreme Court rejected the appellants’ argument, formulating its conclusions on the matter in paragraphs [66]–[68] of the judgment. The first of these in particular is worth quoting in full:

The debate as to whether article VI created fundamental rights in relation to trade, whether the Acts of Union are statutes of a constitutional character, whether the 2018 and 2020 Acts are also statutes of a constitutional character, and as to the correct interpretative approach when considering such statutes or any fundamental rights, is academic. Even if it is engaged in this case, the interpretative presumption that Parliament does not intend to violate fundamental rights cannot override the clearly expressed will of Parliament. Furthermore, the suspension, subjugation, or modification of rights contained in an earlier statute may be effected by express words in a later statute. The most fundamental rule of UK constitutional law is that Parliament, or more precisely the Crown in Parliament, is sovereign and that legislation enacted by Parliament is supreme. A clear answer has been expressly provided by Parliament in relation to any conflict between the Protocol and the rights in the trade limb of article VI. The answer to any conflict between the Protocol and any other enactment whenever passed or made is that those other enactments are to be read and have effect subject to the rights and obligations which are to be recognised and available in domestic law by virtue of section 7A(2).

While the first sentence of this paragraph refers to ‘the debate’ in the singular, it is actually concerned with two distinct issues.

One issue, immediately disposed of in the next sentence, is whether article VI created any fundamental rights protected by ‘the interpretative presumption that Parliament does not intend to violate fundamental rights’. That issue is academic, we are told, because even if the article does create such rights, and even if there is such a presumption, section 7A(3) is surely sufficient to displace it. For reasons of space, I shall limit my discussion on this point to the observation—to which I will return at the end—that the Court appears here to accept the appellant’s (uncontested) argument that the principle of legality extends to fundamental rights created by statute.

The other issue is whether the 1800 Acts of Union are constitutional statutes immune from implied repeal; and if so, whether they could enjoy this immunity vis-à-vis the 2018 and 2020 Acts even if these latter Acts, too, are constitutional. This second issue, we are told, is academic because the ‘clear answer … expressly provided by Parliament in relation to any conflict between the Protocol and the rights in the trade limb of article VI’ is that ‘any other enactment whenever passed or made … [is] to be read and have effect subject to’ the directly applicable provisions of the Withdrawal Agreement.

Was the Issue Really ‘Academic’?

But thus stated, this latter argument appears incomplete. It is true that section 7A(3) expressly provides for the primacy of the Withdrawal Agreement over other enactments. But it does not expressly indicate that these ‘other enactments’ include the 1800 Acts of Union, and neither does this conclusion seem ‘irresistible’ in the light of the words used. A catch-all phrase such as ‘every enactment’ could, imaginably—and even if we think it should not—be read to leave Acts of fundamental constitutional significance out. This is all the more imaginable in the context of, on the one hand, the dicta in HS2 (R (Buckinghamshire County Council) v Transport Secretary [2014] UKSC 14 [207]–[208] per Lord Neuberger and Lord Mance); and on the other hand, the fact that parliamentary legislation was not explicitly included in the definition of ‘enactment’ provided in section 20 of the 2018 Act. As had been pointed out in the course of argument, it went without saying that Acts of Parliament—in general—were to be included within the definition. But it was not necessarily as obvious that constitutional statutes in particular were to be included too.

If so, the question of whether the statutes in issue were constitutional statutes, and of how this would affect their interaction, was anything but ‘academic’. So why did the Court call it that? Two possible explanations suggest themselves.

The first, hinted at in the third sentence of paragraph [66], could be that the Acts of 2018 and 2020 were enacted laterthan the 1800 Acts of Union. But for one thing, it is not easy to see how this could be the decisive factor, at least not without engaging with the supposedly ‘academic’ debate that the Court so scrupulously avoided. And in any event, this explanation would sit at odds with the Court’s apparent acceptance, in the last sentence of paragraph [66], that section 7A(3) could also apply to enactments made after its entry into force. This latter difficulty especially points towards another explanation.

This second, alternative explanation could be that the question as to the constitutional status of section 7A(3) and article VI was neither here nor there because there was no scope for implied repeal in any event. While article VI did conflict with section 7A(2), their conflict was resolved explicitly—by section 7A(3). Section 7A(3), in its turn, did not conflict with article VI, so there could be no implied repeal there either. But if implied repeal was out of the question, there was nothing that the Thoburn doctrine could apply to. Perhaps this was what the Court had in mind when it insisted, in paragraphs [67]–[68], that section 7A did not repeal, but only modified (suspended, subjugated) article VI.

Statutory ‘Subject to’ Clauses

This would be a plausible approach (if the Court indeed took it). There really was no conflict between article VI and section 7A(3). Article VI is a ‘first-order’ (so to speak) statutory clause regulating the relative legal status of the subjects of Great Britain and Ireland. Section 7A(3), by contrast, is a ‘second-order’ provision, resolving conflicts between section 7A(2) and other enactments by providing that all such other enactments, ‘whenever passed or made’, have to be read and given effect ‘subject to’ section 7A(2) and the Withdrawal Agreement it incorporates.

Generally, there can be no inconsistency between a first-order clause and a second-order ‘subject to’ clause which provides that the first-order clause is to be read and given effect subject to some other first-order clause. This is so even when the two first-order clauses themselves are inconsistent. Contrast the following two statements:

  • The law is that p. The law is that not-p.
  • All that follows is to be understood as subject to the statement that the law is that p. The law is that not-p.

The first statement is incoherent, at least as a statement of the law. It does not really tell us what the law is. The second statement, by contrast, may be very odd, but not incoherent. It does tell us what the law is—namely, that the law is that p—and it tells us that in an unambiguous and explicit, if also complex, manner.

Back to Factortame

If the above argument works, we should revisit the reading of Factortame (No 1) (R v Transport Secretary, ex p Factortame [1990] 2 AC 85) which gave the initial impulse for the development of the Thoburn doctrine: that ‘in Factortame (No 1) the House of Lords effectively accepted that section 2(4) [of the European Communities Act 1972]could not be impliedly repealed, albeit the point was not argued’ (Thoburn, paragraph [61]).

Section 2(4) of the 1972 Act was analogous to section 7A(3): it too was a ‘subject to’ clause, subordinating ‘any enactment passed or to be passed’ to, inter alia, section 2(1) of the same Act. Section 2(1), in turn, was analogous to section 7A(2): it incorporated directly applicable Community law into UK law. Laws LJ’s reasoning was that section 2(4) had to be immune from implied repeal because it would have otherwise been susceptible to implied repeal by any later legislation—such as the Merchant Shipping Act 1988—that conflicted with the Community law incorporated by section 2(1). But we now see that this was a false premise. In fact, immune or not, section 2(4) would not have been susceptible to implied repeal by the 1988 Act, because section 2(4) did not conflict with the 1988 Act—section 2(1) did. And section 2(4) not only did not conflict with the later Act but could not conflict with it. As a second-order ‘subject to’ clause, it could not conflict with a first-order provision whose application it modulated. (For a similar argument in relation to section 2(2) of the 1972 Act, see paragraph [50] of Laws LJ’s judgment).

In other words, what was protected from implied repeal in Factortame was section 2(1), and the directly applicable Community law it incorporated into UK law; not thanks to a common law doctrine of ‘constitutional statutes’, however, but because of section 2(4). Section 2(4), by contrast, did not need any protection from implied repeal by the Merchant Shipping Act, because the 1988 Act was not inconsistent with it. Nor could it have been. The concerns which Laws LJ sought to meet in Thoburn had already been met.


I have argued that the Thoburn doctrine of constitutional statutes could not apply in Re Allister because there was in that case no question of implied repeal to begin with. On a proper analysis, section 7A did not conflict with article VI in any way which had not been regulated explicitly. While I am not entirely sure if this analysis was in fact adopted by the Supreme Court, there are hints to that effect in the judgment, and in any case, it makes good sense of the decision.

The analysis has deep implications for the doctrine of constitutional statutes. An analogous analysis of section 2 of the European Communities Act 1972 reveals that the doctrine was never necessary to explain the special protection granted to EU law before Brexit, and after Brexit, to the Withdrawal Agreement. And while it is true that the doctrine had a second objective—to secure a measure of interpretative ‘entrenchment’ for fundamental rights created by statute—it now appears from Re Allister that this objective, too, can be achieved through other means: the principle of legality may simply extend to all fundamental rights, common law and statutory alike.

In effect, it is not clear what independent work the doctrine could do. But then the question of whether this or that Act of Parliament is a constitutional statute becomes not just academic, but idle. Nothing at all hangs, in law, on how it is answered.

I thank Tom Adams, Michael Gordon, and Paul Scott for helpful comments on earlier drafts of this post.

Kacper Majewski is a Lecturer in Law at Lady Margaret Hall, University of Oxford, and a DPhil candidate at Balliol College, University of Oxford.

(Suggested citation: K. Majewski, ‘Re Allister: The End of ‘Constitutional Statutes’, U.K. Const. L. Blog (21st February 2023) (available at https://ukconstitutionallaw.org/))