Brexit On Ice? Court Rules That Only UK Parliament Can Trigger Article 50

Executive Summary

Earlier today, the High Court of Justice ruled that the U.K. government does not have the constitutional capacity to trigger the U.K.'s withdrawal from the European Union without further primary legislation being passed. This decision is likely to delay, potentially significantly, the filing of the U.K.'s Article 50 notice with the European Council, further extending the uncertainty over the timing and the terms of the U.K.'s exit from the European Union ("EU").

Background

During the course of October 2016, a number of separate claims were commenced in the High Court concerning the U.K. government's constitutional capacity to give notice under Article 50 TFEU of the U.K.'s intention to withdraw from the EU. These various proceedings were joined and heard together as Santos & Miller v. Secretary of State for Exiting the European Union.

The primary purpose of the relevant claims was for the High Court to determine whether the U.K. government may lawfully use what are referred to as "prerogative powers" to serve a notification under Article 50 TFEU of the U.K.'s intention to withdraw from the EU. These prerogative powers are a quirk of U.K. constitutional law, which allows the government at the time (acting, effectively, on behalf of the Monarch) to conclude certain international treaties and agreements, without a specific enabling Act of Parliament having been passed authorizing the relevant agreement or treaty. In planning to file the U.K.'s notice under Article 50 in March 2017, the U.K. government and Prime Minister had been relying on these prerogative powers. This situation arose by virtue of the fact that the legislation that enabled the June referendum did not provide any statutory framework for filing a notice under Article 50. This is why many commentators refer to the referendum as having been "advisory" in nature.

Key Points of the Judgment

The judgment handed down today is emphatic in upholding the principle of Parliamentary Sovereignty. The submissions made by the government are analysed and dismissed in some detail throughout the judgment. In particular:

Parliament explicitly has the power to repeal the European Communities Act of 1972, which is the key U.K. statute giving EU law effect in the U.K. It is a fundamental principle of U.K. constitutional law that the prerogative powers referred to above do not give the government the power to "displace" primary legislation or enable the government to vary the "law...