The Supreme Court judgment in Gina Miller is not merely an affirmation of what the High Court said. The eight member majority confirmed the earlier decision, but also took the opportunity to restate a fundamental principle, which had been left implicit by the court below. The High Court said that the substantive rights arising out of EU law and the European Communities Act 1972, in employment, environment, consumer protection, competition or free movement, could not be abolished merely by the exercise of the royal prerogative. This was a standard interpretation of existing law, adapted for the context of Article 50. The Supreme Court accepted that this was correct, but added one additional reason.

The Court accepted that membership in the European Union is not merely an act of alliance with other states or an “international” decision. It marks the transformation of a state’s legal order. Membership means that any law made in cooperation with those other states through EU institutions becomes without any intervening step the law of the land. So the European Communities Act 1972 did not merely mark the incorporation of some existing or future identifiable substantive rights, for example in employment, equality, environmental or consumer law. It also marked the creation of a new law-making process.

Withdrawal from the EU under Article 50 will abolish the substantive EU law rights already created. But it will also abolish the cooperative law-making process. This was a further reason to reject the government’s submissions. Such constitutionally significant change, the Supreme Court held, could not happen through exercising the Royal Prerogative. The Supreme Court’s majority says, at par.82, that their conclusion follows from “the ordinary application of basic concepts of constitutional law to the present case”.

It sounds mundane but it is not. It puts beyond doubt something that many have doubted: constitutional change cannot happen in the United Kingdom through practice, evolution or change of opinion, as some constitutional theorists believe. Constitutional change can only happen through the proper channels of democratic law making. This is not said anywhere explicitly in our unwritten constitution, but is now held by the Supreme Court to be true as a “basic concept” of the constitution. The Court’s decision is thus a restatement of the idea that the rules and principles of the constitution have a systematic coherence.

This idea is not new. Since the HS2 judgment, some acts have been held to be so constitutionally important that “implied repeal” is not enough to set them aside. Parliament can only repeal them explicitly. The Supreme Court applied this doctrine to the question of Brexit, making the government’s defeat heavier than it had been at the High Court. Having now said that Brexit is a constitutional matter, it follows that an “implied repeal” of the European Communities Act 1972 will not be enough.

Pavlos Eleftheriadis is a fellow of Mansfield College, Oxford and a barrister at Francis Taylor Building.

(Suggested citation: P. Eleftheriadis, ‘The Systematic Constitution’, U.K. Const. L. Blog (30th Jan 2017) (available at https://ukconstitutionallaw.org/))