The UK Supreme Court has given its judgment in the matter of R (on the application of Miller and another) v Secretary of State for Exiting the European Union [2017] UKSC 5 – more commonly known as “the Article 50 Brexit appeal”.

The Court, by a majority of 8:3, has ruled that the UK Government cannot trigger Article 50 of the Treaty on European Union, giving notice of the UK’s exit of the EU, without this action first being authorised by an Act of Parliament. The Court also held, unanimously, that there is no requirement for the UK Government to consult with the devolved legislatures of Scotland, Wales and Northern Ireland, before giving notice under Article 50.

As anticipated, the judgment, at 96 pages in length, is a watershed moment for constitutional law in the UK. The judgment enshrines the overall sovereignty of the UK Parliament and casts new light on the Union’s relationship with its devolved legislatures.

Why did the Court uphold Parliament’s involvement in the triggering of Article 50?

The majority judgment, given by Lord Neuberger, the President of the UK Supreme Court, outlines eight key reasons why Parliamentary authority is required before the Government can trigger Article 50:

  1. The Court held that EU law was an independent and overriding source of UK law, by virtue of the effect of section 2 of the European Communities Act 1972.
  2. By leaving the EU, the Court’s view was that UK domestic law will change and that rights enjoyed by UK residents through EU membership will be affected.
  3. Withdrawal from the EU will be a fundamental change to the UK’s constitutional arrangements, by cutting off a source of domestic law. The Court held that such a change must be effected by Parliament, according to the constitutional requirements of the UK.
  4. The removal of existing rights enjoyed by UK citizens meant that the UK Government was not entitled to act alone without Parliamentary approval.
  5. The language of section 2 of the European Communities Act 1972 did not envisage withdrawal by an act of the Crown alone; had that been intended, it would have been made express.
  6. The fact that Parliament could hold the Government to account after the triggering of Article 50 did not address the point, if the Government does not have the requisite constitutional power to act in the first place.
  7. Subsequent EU-related legislation and events after 1972 are consistent with an assumption by Parliament that no power exists to withdraw the UK from treaties without an Act of Parliament.
  8. The Act of Parliament which paved the way for the June 2016 referendum only allowed for the “holding” of the referendum, without specifying its consequences. Accordingly, an Act of Parliament is required before the Government may trigger Article 50.

The result is a judgment which highlights the strength, power and supremacy of the UK Parliament, which is confirmed as sovereign and ultimately, senior to government ministers in the hierarchical matrix of the UK constitution.

What about Scotland, Wales and Northern Ireland?

In relation to the devolution settlements for Scotland, Wales and Northern Ireland, the Court held that while these arrangements were made at the time on the assumption the UK would be a member of the EU, they do not require it. Foreign affairs are a matter reserved solely for the UK Government.

Although the “Sewel Convention” (through which the UK Government will not normally legislate in respect of devolved matters, without the consent of the Scottish Parliament and Welsh and Northern Irish Assemblies) is acknowledged as an important political constraint on the activities of the UK Parliament, the Court has held that its operation in practice is not a matter for the Courts. While the Sewel Convention may embody an “expectation”, it does not amount to a legal rule which can be enforced and policed by the Courts. The Court emphasises that it does not underestimate the importance of the Sewel Convention politically, but says that the Courts do not have a remit to enforce it. Accordingly, the Court has held that there is no legal requirement for the devolved legislatures of Scotland, Wales and Northern Ireland to be consulted before triggering Article 50.

What happens next?

The UK Government has confirmed that a short Bill will be introduced “within days”. The Bill is anticipated to be brief and straightforward, with minimal scope for amendment or derailment by opposition parties. With MPs in the House of Commons largely expected to vote in favour of the Bill, any scope for derailment is likely to come at the stage of House of Lords’ scrutiny of the Bill. The Lords’ unelected status may however ward off any heavy intervention on their part, into what is a highly charged and emotive political issue in the UK, following the results of the June 2016 referendum.

In Scotland, the First Minister, Nicola Sturgeon has indicated that the Scottish Parliament will, nevertheless, hold a vote on the triggering of Article 50. The Scottish Parliament would be expected to refuse consent in that vote. Assuming that happens, the scene is set for the UK Government to be perceived as ignoring the will of the Scottish Parliament. For many observers, that narrative seems likely to bring further hard political issues in the UK constitutional settlement to the fore. It may well lead to calls for a further referendum on Scottish independence.

While the UK Supreme Court’s decision provides clarity on the fundamental and supreme sovereignty of the UK Parliament in the UK constitution, it leaves open for another day hard questions of a political nature on the UK’s future relationship with its devolved nations.

Engage with the decision

The decision and its accompanying press summary can be read here.