Sources - Sovereignty, supremacy of EC law enforced by ECJ disapplying UK law

The supremacy of EC law enforced by the ECJ. If a provision of national law conflicts with a provision of EC law, then EC law prevails.

Van Gend en Loos v The Netherlands [1963] ECR

"The Community constitutes a new legal order of international law for the benefit of which the states have limited their sovereign rights, albeit within limited fields."

Costa v ENEL [1964] ECR

"the EEC Treaty has created its own legal system which…became an integral part of the legal systems of the Member States and which their courts are bound to apply."

"Member States have limited their sovereign rights, albeit within limited fields, and have thus created a body of law which binds both their nationals and themselves."

"The executive force of Community law cannot vary from one State to another in deference to subsequent domestic laws, without jeopardizing the attainment of the objectives of the Treaty."

Member States have permanently limited their sovereign rights.