Since writing this post, I have written a longer article for the Cambridge Law Journal critically examining the Supreme Court’s decision in Miller. A pre-publication draft of the article can be downloaded here. For a briefer overview of the Miller judgment, see this post in my 1,000 words series.

On 24 January 2017, the UK Supreme Court gave judgment in the Miller case, in which the Government sought to establish that it could initiate the UK’s withdrawal from the EU without reference to Parliament. The Supreme Court also considered whether the UK’s devolution arrangements impacted upon the Government’s capacity to trigger Article 50 of the Treaty on European Union. On the question whether Article 50 could be invoked using prerogative power, the Supreme Court ruled, by an 8–3 majority, against the Government. On the devolution issue, the Court ruled unanimously that there was no legal requirement to consult or secure the consent of devolved institutions.

In this post, I aim to do three things. First, I examine three key elements of the majority’s reasoning, noting significant differences between it and Lord Reed’s dissent (with which Lords Carnwath and Hughes agreed). Second, I reflect on what underlies the disagreement between the majority and the dissentients. Third, I consider the wider constitutional significance of Miller.

Key aspects of the majority judgment

In concluding that the Government could not use prerogative power to trigger Article 50, the majority relies upon three interlocking arguments concerning: the relationship between EU and UK law; the operation of the European Communities Act 1972 (‘ECA’); and the scale of the constitutional impact of EU membership.

The relationship between EU and UK law

The majority places great weight on the notion that EU law is a ‘source of UK law’. Indeed, that notion is pivotal to its analysis. The majority concedes that ‘[i]n one sense’ UK law, in the form of the ECA, ‘is the source of EU law’, because ‘without that Act, EU law would have no domestic status’. However, without repudiating that analysis, the majority declares it inadequately ‘realistic’, and states it preference for the view that ‘it is the institutions of the EU which are the relevant source of [EU] law’. Thus, says the majority, while the ECA ‘gives effect’ to EU law, it is not itself ‘the originating source of that law’. Rather, EU law is ‘an independent and overriding source of domestic law’ (my emphasis).

The EU Treaties, EU legislation and the interpretations placed on these instruments by the Court of Justice are direct sources of UK law. — Majority judgment

The majority reaches this conclusion while simultaneously holding that the ‘rule of recognition’ — ‘the fundamental rule by reference to which all other rules are validated’ — has remained unaltered by EU membership. That view, although at odds with the classical analysis of the Factortame case advanced by Professor Sir William Wade, is defensible. As Lord Reed puts it in his dissent, EU law derives its authority from a statute (viz the ECA) and the statute derives its authority from the rule of recognition. EU law’s validity in the UK does not therefore turn upon any modification of the rule of law recognition. However, whereas the majority sees no tension between this conclusion and its view that EU law is an independent source of UK law, it drives Lord Reed to the opposing view that ‘EU law is not itself an independent source of domestic law, but depends for its effect in domestic law on the 1972 Act’ (my emphasis). The Act gives effect in domestic law to EU law, but the latter is not assimilated to the former, and there has been no change to ‘any fundamental constitutional principle in respect of the identification of sources of law’.

Lord Reed’s analysis of this axiomatic point seems to me compelling, the weakness of the majority’s position being highlighted by the tension barely concealed within it. It is hard to see in what sense the EU’s legislative and constitutional apparatus can be an ‘independent source’ of UK law if the source of EU law’s validity in the UK is itself UK law (in the form of the ECA). The EU regime may be independently capable of generating law — and so be a source of law — viewed from an EU perspective, but it does not follow that the same is true from a UK constitutional perspective, as the Supreme Court itself appeared to acknowledge in the HS2 case.

This disagreement between Lord Reed and the majority goes to the heart of how each approaches the question whether the prerogative can be used to trigger Article 50. For the majority, once EU law is treated as a source of domestic law, the prerogative power to conduct foreign relations ceases to be relevant. The question, on this analysis, is not whether the foreign relations prerogative has been curtailed, because it is simply not fit for purpose when it comes to triggering Article 50. It is therefore beside the point: if the effect of Article 50 is to set in train a process that will change domestic law, the matter is not one of foreign relations in the first place. In contrast, because he does not view EU law as a source of UK law — and for interlocking reasons that flow from his analysis of the ECA, to which I turn below — the foreign relations prerogative remains pertinent for Lord Reed. The invocation of Article 50 can, on this view, take the form of a prerogative act operating on the international plane: triggering withdrawal does not involve the removal of rights that are domestic law rights in the traditional sense or the removal of a source of UK law. The majority and Lord Reed thus approach the question from diametrically opposing perspectives. For the majority, there is no question of prerogative authority extending to the triggering of Article 50, and the issue is therefore whether the ECA (or other legislation) creates a power to do so (which, they hold, it does not). For Lord Reed, in contrast, the foreign relations prerogative remains exercisable unless legislation precludes its use (which, he concludes, it does not).

The European Communities Act 1972

Against that background, it is significant that that the majority and Lord Reed also fundamentally disagree about the nature and purpose of the ECA. According to the majority, the ECA neither ‘contemplates’ nor ‘accommodates’ the ‘abrogation of EU law’ by a prerogative act effecting withdrawal. Rather, through the ECA, Parliament ‘endorsed and gave effect to the UK’s membership’ of the EU in a way that is inconsistent with withdrawal via the prerogative. On this analysis, it was Parliament’s intention in 1972 that the UK should be a member of the EU (and, by implication, that it should remain so unless Parliament were to provide otherwise). This suggests that even if a relevant prerogative power were potentially in play, its exercise so as to institute withdrawal would be incompatible with, and so precluded by, the ECA.

[The ECA] simply creates a scheme under which the effect given to EU law in domestic law reflects the UK’s international obligations under the Treaties, whatever they may be. — Lord Reed

Lord Reed, meanwhile, sees the purpose of the ECA in quite different terms: it ‘imposes no requirement, and manifests no intention, in respect of the UK’s membership of the EU’. The Act, on this view, is nothing more than a ‘scheme under which the effect given to EU law in domestic law reflects the UK’s international obligations under the Treaties, whatever they may be’. Lord Reed bases this analysis in part upon the fact that section 2(1) of the ECA provides for the domestic legal effect only of such rights as are provided for by the Treaties ‘from time to time’. (I made a similar argument here.) Hence: ‘Withdrawal under article 50 alters the application of the 1972 Act, but is not inconsistent with it.’ Lord Reed’s analysis of the right to vote in European elections — provided for by the European Parliamentary Elections Act 2002 — is to similar effect (as was mine). The right, says Lord Reed, is ‘obviously conditional on the UK’s continued membership of the EU’. Such rights will cease to be effective if the UK leaves, but that is ‘inherent’ in the nature of such conditional rights: ‘The only logical alternative is to hold that Parliament has created a right to remain in the EU, and none of the arguments goes that far.’

Constitutional ‘scale’

Which of the two rival interpretations of the ECA scheme should be preferred is one of the thorniest issues raised by Miller. But the merits of the Justices’ competing positions become clearer when their underlying reasoning is examined. For the majority, that reasoning turns in part upon what might be called constitutional ‘scale’ — that is, the scale of EU membership’s constitutional implications and the (resulting) scale of the implications of withdrawal. The majority says that ‘in constitutional terms the effect of the 1972 Act was unprecedented’, not least because, ‘for the first time in the history of the UK, a dynamic, international source of law was grafted onto, and above, the well-established existing sources of domestic law: Parliament and the courts’. On this view, withdrawal ‘will constitute as significant a constitutional change as that which occurred when EU law was first incorporated in domestic law by the 1972 Act’. It follows, says the majority, that it would be ‘inconsistent with long-standing and fundamental principle for such a far-reaching change to the UK constitutional arrangements to be brought about by ministerial decision or ministerial action alone’. With similar imprecision, we are told that ‘a major change to UK constitutional arrangements can[not] be achieved by a ministers alone’ and must be ‘effected in the only way that the UK constitution recognises, namely by Parliamentary legislation’. But that, of course, merely begs the question.

In any event, the majority considers this argument of scale to be an answer to the contention that the ECA is ‘ambulatory’ or ‘contingent’ in the sense that it does no more than give effect to whatever EU obligations the UK has at any given time without presupposing or requiring that there will be any such obligations. The majority thus concludes that while the ECA accommodates changes to EU law made by the EU institutions or through treaty variation, the ECA does not accommodate the possibility of ‘complete withdrawal’, which is said to represent ‘a change which is different not just in degree but in kind from the abrogation of particular rights, duties or rules derived from EU law’.

[A] major change to UK constitutional arrangements can[not] be achieved by ministers alone … [Such changes can be] effected in the only way that the UK constitution recognises, namely by Parliamentary legislation. — Majority judgment

It is true that withdrawal is, in a factual sense, different in scale from (say) an EU legislative act that narrows or removes a given right or set of rights. Complete withdrawal self-evidently removes more rights than EU legislative action that might change, diminish or remove rights. It is also true that withdrawal entails action initiated by the UK rather than action undertaken by EU institutions (with whatever involvement by Member States is required by EU law). But is the distinction legally relevant by reference to the terms of the ECA? Lord Reed thinks not. He argues that there is ‘no basis in the language of the 1972 Act’ for drawing any distinction between ‘variations in the content of EU law arising from new EU legislation, and changes resulting from withdrawal by the UK from the European Union’. For that reason, the ECA, on Lord Reed’s reading of it, is capable of accommodating the triggering of Article 50 because complete withdrawal does not fall into a category of matters legally distinct from the variation of EU law by means of the enactment of EU legislation. All such matters, on this view, are already catered for by the ECA, because of the conditional way in which it provides for domestic effect of EU law. Lord Reed’s reading of the ECA on this point is consistent with my own. I see no textual basis for the distinction drawn by the majority, and the argument of ‘scale’ seems at best a questionable, and inexact, basis for interpolating such a distinction.

The underlying disagreement

The disagreement between the majority and minority Justices may appear to — and to some extent does — turn upon differences over technical matters such as the construction of the text of the ECA and other relevant legislative instruments. But it is tolerably clerar that beneath disagreement about such matters lie considerations that are more profound, if less precise, in nature. Two such matters are worth highlighting.

Contrasting perspectives on EU law

It is evident that the majority and the dissentients have fundamentally different views about the constitutional status that EU law has (and will, until Brexit, continue to have) within the UK’s legal system. For instance, while the majority acknowledges that the UK is and remains a ‘dualist’ system, it evidently takes the view that EU law, once given the green light by the ECA, ceased to be nothing more than a distinct body of treaty-based law that was ascribed certain effects within the UK, and instead became not just a juridically integral part of domestic law but an independent source of such law. As the majority put it, EU law, on this analysis, was ‘grafted onto’, and so became a facet of, UK law. Once that perspective is adopted, the rest of the majority’s analysis follows ineluctably. If EU law really has that status, then it is unsurprising that the foreign relations prerogative cannot be used in order to initiate EU law’s excision from the corpus of domestic law: only Parliament can wield (or at least hand the Government) the scalpel. Lord Reed, in contrast, takes the view that EU law remains a body of law that is distinct from domestic law: thus the ECA ‘did not create statutory rights in the same sense as other statutes, but gave legal effect in the UK to a body of law now known as EU law’.

This disagreement about the nature of EU law and its place within the UK legal system is one that does not admit of easy resolution. It is, I would venture, ultimately a question that turns upon the perspective one adopts concerning the extent to which EU law has been integrated into and become a part of domestic law. But to the extent that the majority’s position is coloured — as it clearly is — by its premise that EU law is an ‘independent’ source of law, it is highly questionable, at least in the light of the majority’s insistence that the rule of recognition has not changed. At any rate, the majority’s position raises — but does not definitively answer — a range of interesting questions about exactly what it is that caused EU law to acquire that status, and (therefore) to what extent other bodies of treaty-based law might acquire a similar status. Such questions will assume practical relevance when in the future issues arise about the extent to which the analysis of the majority in Miller is applicable in other contexts. It may well, at that point, be necessary to nail down in terms far more exact than those offered by the majority what factor or combination of factors caused EU law to acquire the juridical status now ascribed to it.

Political and legal control of the executive

The second underlying difference that helps to explain the disagreement between the majority and minority judges concerns the extent to which the possibility of parliamentary control of the executive should be taken into account when determining the appropriate extent of judicial control. Lord Reed touches upon this matter in the context of the concern — raised by the majority — that if the prerogative could have been used to trigger Article 50, the executive could at any point have triggered Brexit without any referendum mandate. The majority is dismissive of judicial review as a safeguard against casual executive-initiated withdrawal, on the ground that the exercise of the foreign relations prerogative is non-justiciable. Lord Reed approaches the matter from a different angle, arguing that ‘controls over the exercise of ministerial powers under the British constitution are not solely, or even primarily, of a legal character’. It follows that: ‘For a court to proceed on the basis that if a prerogative power is capable of being exercised arbitrarily or perversely, it must necessarily be subject to judicial control, is to base legal doctrine on an assumption which is foreign to our constitutional traditions.’ Lord Reed’s invocation of this point is readily comprehensible in terms of its relevance to the legal analysis; it reduces to the argument that concerns about the courts’ limited capacity to control the exercise of certain prerogative powers should not lead a court that is otherwise satisfied that the relevant power exists to doubt its existence.

For a court to proceed on the basis that if a prerogative power is capable of being exercised arbitrarily or perversely, it must necessarily be subject to judicial control, is to base legal doctrine on an assumption which is foreign to our constitutional traditions. — Lord Reed

Lord Carnwath, in his dissent, arguably places greater weight on the possibility of accountability to Parliament. He underlines the importance of acknowledging ‘the sensitivity in our constitution of the balance between the respective roles of Parliament, the Executive and the courts’. And he is critical of the Divisional Court for having examined the matter in a binary way, arguing that it is wrong to see the issues raised by Miller in terms of ‘a simple choice’ between parliamentary sovereignty and ‘untrammelled’ prerogative power. This, argues Lord Carnwath, is to overlook the fundamental importance of executive accountability to Parliament for the exercise of its legal, including its prerogative, powers.

It is not clear from Lord Carnwath’s judgment how far he seeks to press this analysis. However, he appears to assume that the possibility of accountability to Parliament might have some effect upon the court’s analysis of whether a given prerogative power exists. In particular, he concludes in the light of the resolution of the House of Commons adopted in December 2016 — calling on the Government to invoke Article 50 by 31 March 2017 — that ‘the formality of a Bill is unnecessary to enable Parliament to fulfil its ordinary responsibility for scrutinising the government’s conduct of the process of withdrawal’. Of course, the fact that the use of a given power has been or may be scrutinised by Parliament can, at least in some circumstances, serve to blunt the intensity of any judicial review of its exercise. But the Court in Miller was asked to determine whether the Government possessed relevant prerogative power. It is not immediately obvious from Lord Carnwath’s judgment how the possibility of parliamentary oversight might serve to alter the approach of a court faced with such an existential question — or that it should. It is clearly correct that, as Lord Carnwath puts it, ‘The Executive is accountable to Parliament for its exercise of the prerogative, including its actions in international law.’ But Lord Carnwath does not explain how or why that might affect the determination of whether, in the first place, the Government possesses a relevant prerogative power. It is one thing to suggest (as I understand Lord Reed to have done) that a lack of judicial control should not impact upon the court’s analysis of the prerogative’s existential status. But if Lord Carnwath intends to go further, by suggesting that the availability of political accountability might drive the court towards the conclusion that a given power does exist, that strikes me as problematic.

Broader constitutional implications

What of the broader constitutional implications of Miller? It is doubtless a highly significant decision, both in terms of legal doctrine and its political ramifications. However, its wider constitutional consequences might turn out to be more contained than had perhaps been anticipated.

Prerogative power generally

As I noted above, Miller raises — without clearly answering — questions about the extent to which prerogative power may be constrained by other treaty-based arrangements. However, it seems likely that the shadow cast by Miller over the prerogative will be relatively modest. That follows in large part because so much of the majority’s reasoning appears to rest upon the particularities of EU law and the way in which it has been accommodated at the domestic level (in particular by becoming an ‘independent source’ of domestic law). It would be rash to suggest that Miller forecloses the possibility of other treaty-based arrangements being susceptible to a similar analysis, but Miller certainly does not drive a coach and horses through the foreign relations prerogative.

Parliamentary sovereignty

Nor — on the face of it, at least — does the judgment in Miller break significant ground in terms of parliamentary sovereignty. Indeed, the majority is at pains to emphasise the centrality of that principle, to demonstrate that its judgment operates in the service of the sovereignty of Parliament, and to articulate the implications of EU membership in a manner that is compatible with — rather than, as Wade argued, an existential threat to — it. Judicial analysis at apex court level has been scant over the last four decades as far as the implications of EU membership for parliamentary sovereignty are concerned, Factortame itself, perhaps surprisingly, having cast relatively little light on this matter. The possibility arose of the Supreme Court in Miller — given the nature of the issues raised by the case — offering a more thoroughgoing, and perhaps even novel, analysis of these issues. However, the Court chose, perhaps wisely, to be economical in this area.

Sovereignty, we are told by the majority, is ‘a fundamental principle of the UK constitution’, and the ‘unprecedented state of affairs’ wrought by EU membership — having itself been brought about by Parliament — ‘will only last so long as Parliament wishes: the 1972 Act can be repealed like any other statute’. Thus the majority (like Lord Reed) rejects, as already noted, any suggestion that the rule of recognition has been altered by EU membership. EU law, it follows, ‘can only enjoy a status in domestic law which that principle allows’. This analysis is consistent with that advanced by Lords Mance and Reed in the HS2 case. For reasons that I have explored elsewhere, HS2 arguably broke new ground so far as our understanding of how the EU primary doctrine and the sovereignty of Parliament can co-exist. But Miller does not take us substantially further in that regard.

The only real novelty is the majority’s view that Parliament is capable of legislating so as to institute a source of UK law that is independent of the legislation enacted to achieve that outcome — a conclusion that arguably presses even the ample notion of legislative supremacy beyond its logical boundaries. But since the majority insists that this conclusion is compatible with received wisdom, Miller hardly constitutes a conscious or deliberate challenge to that wisdom. Whether it is subsequently understood as such remains to be seen. (On the subject of novelty, I pass over the majority’s bizarre suggestion that Parliament can ‘create’ prerogative powers.)

Devolution and the territorial constitution

If — as we now know it is — legislation is needed to trigger, or to authorise the triggering of, Article 50, then the question arises (1) whether such legislation falls within the Sewel Convention. If it does, then two further questions arise: (2) whether the Convention is justiciable by the Court, and (3) whether the Convention has been rendered justiciable by being transformed into a legal requirement by operation of the Scotland Act 2016. The Court answers questions (2) and (3) in the negative, and therefore declines to answer question (1).

Judges … are neither the parents nor the guardians of political conventions; they are merely observers. — Majority judgment

According to the majority, judges ‘are neither the parents nor the guardians of political conventions; they are merely observers’: while they can ‘recognise the operation of a political convention in the context of deciding a legal question’, they cannot ‘give legal rulings on its operation or scope, because those matters are determined within the political world’. This perhaps exaggerates the degree of judicial reticence that has hitherto been exhibited in relation to conventions: in particular, the Upper Tribunal in Evans v Information Commissioner expended considerable time and effort delineating and analysing conventions relating to the role of the heir to the throne. But the thrust of the Supreme Court’s judgment in this area is as plain as it is broadly orthodox — that conventions are creatures of the political, not the legal, realm.

That, however, leaves the question whether the Scotland Act 2016 has changed the status of the Sewel Convention. It inserts a new section 28(8) into the Scotland Act 1998, glossing the latter’s stipulation that it ‘does not affect the power of the Parliament of the United Kingdom to make laws for Scotland’ with the proviso that it is ‘recognised’ that the UK Parliament ‘will not normally legislate with regard to devolved matters without the consent of the Scottish Parliament’. (The Wales Bill, currently before Parliament, makes similar provision in respect of the Welsh Assembly.) The Supreme Court concluded that this did not ‘convert the Sewel Convention into a rule which can be interpreted, let alone enforced, by the courts’, and that ‘the purpose of the legislative recognition of the convention was to entrench it as a convention’ (my emphasis). It is not entirely clear what, in this context, ‘entrench’ means, but it presumably means that the convention is, by legislation, politically entrenched in the sense that the legislation underlines and adds political weight to the convention, without going so far as to transform it into something other than a convention. Thus, while the majority did not doubt the ‘fundamental role’ of the Sewel Convention, ‘the policing of its scope and the manner of its operation does not lie within the constitutional remit of the judiciary, which is to protect the rule of law’.

It was this aspect of the case that had the capacity to be the most constitutionally explosive. If (improbably) the Court had concluded that the law required devolved consent to legislation triggering Brexit, the political and constitutional implications would have been profound. However, although the Supreme Court declined to reach an immediately earth-shattering conclusion on this point, the conclusion it did reach still has the capacity to substantially destabilise the territorial constitution. That is so not least because it exposes section 28(8) of the Scotland Act — inserted in the aftermath of the Scottish referendum — for the smoke-and-mirrors exercise that it always was. The Supreme Court has now confirmed — correctly, in my view — that statutory ‘recognition’ of a convention does not deprive it of its essential character as a convention. But in clarifying that point, the Court reveals the statutory provision to be nothing more than a political token in legislative garb.

That conclusion will doubtless prove unpalatable to many. But nor does it remove the whole of the sting from arguments based on the Sewel Convention — for while the Court decided the Convention was not legally enforceable, it did not decide that the Convention was inapplicable. Indeed, the First Minister of Scotland has already signalled that, in her view, the Convention does apply, that the UK Government is thus politically obliged to consult devolved institutions, and that the Scottish Government will therefore ‘bring forward a Legislative Consent Motion and ensure that the Scottish Parliament has the opportunity to vote on whether or not it consents to the triggering of Article 50’. If, as is likely, the Scottish Parliament withholds consent, Miller ensures that that will not have the effect of legally blocking Brexit, but it will doubtless complicate the politics.

For that reason, among others, while Miller is the last word on whether Article 50 can be triggered without UK legislation, it is far from the last word on what lies ahead — at least politically and constitutionally — as the UK begins its solitary march down the long road towards Brexit. In that sense, the Supreme Court’s judgment, far from being the beginning of the end, is — at most — merely the end of the beginning.