Abstract
In several recent cases the Supreme Court has endorsed the idea that there are some general limits to incorporation of European Union law in the United Kingdom. The general limits stem from the Court’s interpretation of the European Communities Act 1972, the statute that grounds domestic effect of EU law, construed both in the light of ordinary canons of interpretation and in the light of fundamental principles. This raises the question what are the legal consequences when an EU measure violates one of those limits. In this paper, I propose an answer from the perspective of what a domestic court ought to do. My aim is to develop the legal position emerging from Assange, HS2, Pham, and Miller. I argue that sometimes UK courts are under a duty not to apply EU law. However, the circumstances where this is the case are even more limited than the focus on the general limits of incorporation of EU law may suggest. In particular, fundamental principles of UK law may work to expand the scope of domestic effect of EU law. I want to stress that neither the cited cases, nor the present paper, take a position of hostility towards EU law. The following discussion makes it clear that both EU law and UK law have many devices to avoid conflict and those devices need to be exhausted before a court concludes that it is under a duty not to apply EU law.