pj-150x100-copyThis comment first appeared on Matrix’s Brexit Hub and is reproduced here with kind permission.

The UK Supreme Court decided, by a majority of 8-3, that an Act of Parliament is required before the Government can give notice, under Article 50 of the Lisbon Treaty, of the UK’s intention to leave the European Union. The Court also decided, unanimously, that the consent of the devolved administrations in Northern Ireland, Scotland and Wales was not necessary before notice is given.


Under Article 50(1) of the Lisbon Treaty, the first step for a Member State which wishes to leave the EU is for it to decide to do so “in accordance with its own constitutional requirements”. Having so decided, the Member State must give notice of its intention to the European Council – Article 50(2). That notification starts a two year period to negotiate “the arrangements for its withdrawal, taking account of the framework for its future relationship with the Union”. That period can only be extended with the unanimous agreement of the 27 Member States not seeking to leave.

The issue before the Supreme Court was the UK’s constitutional requirements for the purpose of Article 50(1).

Two possible constitutional requirements were under consideration. First, could the residual prerogative powers of the Crown in the international plane be used by the Government for the purpose of Article 50(1) or was an Act of Parliament required? Second, did all or any of the devolution arrangements require the consent of the devolved administrations as part of the UK’s “constitutional requirements”?

On the first point, the Court decided that the European Communities Act 1972 and subsequent Acts were inconsistent with the retention of any prerogative power enabling Ministers to withdraw from the EU Treaties. It followed that an Act of Parliament was required. The Supreme Court declined to prescribe in any way the form of such an Act.

On the second point, they concluded that the need for a UK Act of Parliament meant they did not need to decide if a separate Act was required for Northern Ireland. They also decided that the Sewel Convention, under which the UK Government would normally seek the consent of the devolved administrations on matters affecting their competence, did not amount to a binding obligation on the UK Government and formed no part of the “constitutional requirements” for the purpose of Article 50.


The Supreme Court has provided clarity about what is required to begin the formal process of leaving the EU. They made clear that this is purely a legal issue and nothing to do with the politics of withdrawal or the UK’s subsequent relationship with the EU. For those who continue to complain about the involvement of the courts in resolving this issue, it is worth noting that the Supreme Court pointed out it would have been open to Parliament when legislating for the referendum to have prescribed, in that legislation, the consequences of the result.

Sir Paul also commented on the judgment in the High Court: Article 50 Judgment: Brexit Case Commentary by Sir Paul Jenkins QC (Hon)