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R (On The Application Of Miller & Anor) v Secretary Of State For Exiting The European Union (2017)


The Government did not have power under the Crown's prerogative to give notice pursuant to TEU art.50(2) for the UK to withdraw from the EU. An Act of Parliament was required.


The secretary of state appealed against a decision that the Government could not give notice of the UK's withdrawal from the EU pursuant to TEU art.50(2) without Parliamentary approval. Devolution questions were raised on a further appeal against a decision that the constitutional arrangements for Northern Ireland did not affect the Government's power to give notice under art.50(2).

The UK had joined the European Communities in 1973. The European Communities Act 1972 gave effect to Community law in the UK. The EC was later superseded by the European Union. A referendum took place in 2016 under the European Union Referendum Act 2015. A majority voted for the UK to leave the EU. A majority in Northern Ireland voted to remain. Article 50 provided that member states could decide to withdraw from the EU in accordance with their own constitutional requirements. It was common ground that notice could not be given conditionally and could not be withdrawn. The Divisional Court held that, because prerogative powers could not be used to change domestic law, ministers could not serve notice without statutory authorisation. The Northern Irish courts referred devolution questions, some specific to Northern Ireland and others raising more general issues regarding consultation with the devolved bodies.


HELD: (Lords Reed, Carnwath and Hughes dissenting as to need for legislation)

Status and effect of 1972 Act - The 1972 Act was the conduit by which EU law was introduced into domestic law. It constituted EU law as an independent and overriding source of domestic law. The rights incorporated into domestic law through s.2 varied with the UK's obligations from time to time under the EU treaties, but provisions of a new treaty were only brought into domestic law once it was statutorily added to the definition of "Treaties" in s.1(2). Parliament could not have intended that s.2 continued to import EU law after the UK ceased to be bound by the treaties, but it did not follow that the Act accommodated the abrogation of EU law upon withdrawal from the treaties by prerogative act. Section 2(1) and s.2(2) ensured that EU law as it stood from time to time was given effect in domestic law; it did not follow from that that prerogative powers could be used to cut off the source of EU law. Upon UK withdrawal, EU law would cease to be a source of domestic law. Even EU rules transposed into domestic law would have a different status: they would no longer be paramount, but subject to domestic repeal or amendment. Withdrawal was a significant constitutional change. If notice was given, that change would occur irrespective of whether Parliament repealed the Act. It would be inconsistent with fundamental principle for such far-reaching constitutional change to be brought about by ministerial action alone, particularly when the relevant source of law had been created by Parliament and given supremacy in the hierarchy of law sources. The prerogative to make and unmake treaties, which operated wholly on the international plane, could not be exercised in relation to the EU treaties in the absence of statutory sanction, R. v Secretary of State for Foreign and Commonwealth Affairs Ex p. Lord Rees-Mogg [1994] Q.B. 552 considered (see paras 60-61, 76-89 of judgment).

Legislation and events after 1972 - Subsequent events did not change the position. Article 50, introduced in 2008, operated only on the international plane; the secretary of state could derive no domestic authority from the fact that the treaties included provision for unilateral withdrawal. The fact that the European Union (Amendment) Act 2008 and the European Union Act 2011 did not specify a prerogative power to withdraw under art.50(2) did not implicitly recognise a prerogative of withdrawal. The fact that a statute said nothing about a topic rarely if ever justified inferring a fundamental change in the law (paras 104-108).

Effect of 2015 Act and referendum - The 2015 Act made no provision for the consequences of either outcome of the referendum. Where implementation of a referendum result required a change in the law, and statute had not provided for that change, the change had to be made in the only way in which the constitution permitted, namely Parliamentary legislation (paras 119-121).

Devolution questions - In providing that the devolved bodies could not act in breach of EU law and empowering them to implement it, the devolution legislation did not require the UK to remain an EU member. Relations with the EU were not devolved matters. The devolved legislatures did not have a parallel legislative competence in relation to withdrawal. As a statute was required to authorise notice, it was not necessary to reach a definitive view on the referred question of whether the Northern Ireland Act 1998 required primary legislation to authorise notice. Section 1 of that Act gave the Northern Irish people the right to determine whether to remain part of the UK. It did not regulate any other change in constitutional status or require the consent of a majority in Northern Ireland to UK withdrawal from the EU. The Sewel convention, that Parliament would not normally legislate on devolved matters without the consent of the Scottish Parliament, did not affect the position. Courts could not give legal rulings on the operation or scope of conventions, because those matters were determined politically. The inclusion of the convention in the Scotland Act 1998 s.28(8) did not make it into a justiciable rule. None of the devolved legislatures had a legal veto on withdrawal (paras 129-135, 146-151).

Appeals dismissed, devolution questions answered

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24 Jan 2017

Supreme Court
Lord Neuberger PSC, Lady Hale DPSC, Lord Mance JSC, Lord Kerr JSC, Lord Clarke JSC, Lord Wilson JSC, Lord Sumption JSC, Lord Reed JSC, Lord Carnwath JSC, Lord Hughes JSC, Lord Hodge JSC

LTL 24/1/2017 : [2017] 2 WLR 583 : Times, January 25, 2017

Benjamin John
Dominic Chambers QC