R (Miller) v Secretary of State for Exiting the EU [2017] UKSC 5

Introduction

R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5 is a landmark constitutional case concerning the use of the royal prerogative to trigger Article 50 of the Treaty on European Union, commencing the process of the UK’s withdrawal from the EU. The case arose following the referendum of 23 June 2016, in which the UK voted to leave the EU. The Supreme Court held that the government could not use prerogative powers to notify the UK’s intention to withdraw under Article 50 and that an Act of Parliament was required. The case is a seminal authority on the relationship between prerogative powers and parliamentary sovereignty.

The Facts

Following the referendum, the government argued that it was entitled to trigger Article 50 by exercise of the royal prerogative in foreign affairs. The claimants, including Gina Miller, sought judicial review, arguing that the government lacked the power to use the prerogative to remove rights conferred by Parliament through the European Communities Act 1972.

The Judgment

The Supreme Court held by a majority of 8 to 3 that an Act of Parliament was required to authorise the notification under Article 50. The court reasoned that the European Communities Act 1972 was a constitutional statute that gave effect to EU law in UK domestic law. Triggering Article 50 would inevitably change domestic law by removing the source of EU law rights. The government could not use prerogative powers to change domestic law or to remove rights that Parliament had enacted.