Parliament gets a vote on Brexit
Toby Vanhegan and Riccardo Calzavara discuss the Supreme Court's ruling that the Crown's prerogative powers cannot be invoked to withdraw from the EU treaties
On 24 January 2017, the Supreme Court handed down judgment in R (Miller) v Secretary of State for Exiting the European Union  UKSC 5, the ‘Brexit case’. In a majority decision of eight to three, it held that in light of the terms and effect of the European Communities Act 1972, and subsequent legislation and events, the royal prerogative could not be invoked by ministers to justify giving notice of withdrawal from the EU under article 50 without prior legislative authority.
The issue for the Supreme Court was whether article 50 could lawfully be triggered by ministers without legislation being passed in both houses of parliament and receiving assent from the Queen. As had the Divisional Court, the Supreme Court emphasised that it was not dealing with the political question of whether the UK should leave the EU, but with the question of how that could lawfully be achieved.
We have previously summarised the parties’ submissions before the court (SJ160/47). The secretary of state’s case was based on the Crown’s prerogative powers to enter into and withdraw from international treaties. He argued that ministers are entitled to exercise that power in relation to the EU treaties, and may therefore trigger article 50 without the need for prior legislation.
The claimants’ case, as it had been before the Divisional Court, was that triggering article 50 set the UK on an irreversible course that would lead to EU law ceasing to have effect in the UK, regardless of whether parliament then repealed the 1972 Act. Some of the EU law rights enjoyed by the claimants would come to an end before parliament could make a decision on the Great Repeal Bill. This would be tantamount to altering the law by ministerial action, or executive decision, without prior legislation, which would be unlawful.
The court held that domestic law rights deriving from EU law – such as employment protection, equal treatment, and free movement rights – would disappear on withdrawal from the EU treaties. Further, the withdrawal would cause a change which would be different in kind and degree from the abrogation of particular rights, duties, or rules derived from EU law. It would constitute as significant a constitutional change as that which occurred when EU law was first incorporated into domestic law by the 1972 Act.
Accordingly, prerogative powers could not be invoked to withdraw from the EU treaties. This conclusion is supported by the fact that the 1972 Act did not provide for prerogative power to be invoked in this way.
In relation to the references from Northern Ireland and the devolution questions, the court held that the Northern Ireland Assembly’s consent is not required before the relevant act of the UK parliament is passed. The lord advocate (for Scotland) and the counsel general for Wales were correct to acknowledge that the Scottish Parliament and the Welsh Assembly did not possess any veto on withdrawal.
The court also noted that although devolution had proceeded on the assumption that the UK would be an EU member, that assumption is consistent with the view that parliament could determine whether the UK would remain so. The devolution legislation did not go further and did not require that membership. Dissenting judgments
Lord Reed (with whom Lord Hughes agreed) dissented, holding that the 1972 Act is inherently conditional on the application of the EU treaties to the UK, and therefore on the UK’s membership of the EU. The Act imposes no requirement, and manifests no intention, in respect of the UK’s continuing membership. It does not, therefore, affect the Crown’s exercise of prerogative powers in respect of membership.
Lord Carnwath, also dissenting, held that although by virtue of triggering article 50 the EU treaties will cease to apply and domestic law will change, it is clearly envisaged that the final form of those changes will be governed by legislation. Accordingly, on the assumption that the Great Repeal Bill becomes law by the time of the withdrawal, the extent to which existing laws are changed or rights taken away will be determined by legislation.
The dissenting justices agreed with the majority in relation to the Northern Irish issues and devolution generally.
Therefore, in the space of 283 paragraphs, set out over 96 pages, the Supreme Court has decided that the government must obtain parliament’s approval before it can give notice of withdrawal from the EU under article 50. On 26 January 2017, two days after judgment was handed down, the government introduced a bill proposing to give the prime minister authority to trigger article 50. The question now is whether parliament, in the short timetable the government has afforded for debate, will give its approval.
In the meantime, a challenge to the assertion that notice under article 50 is irrevocable is expected in the Northern Irish courts, from whence a reference to the Court of Justice of the European Union is expected.
Toby Vanhegan and Riccardo Calzavara are barristers at Arden Chambers