"Parliamentary supremacy": UK law. The historical principle in UK law that the UK Parliament was 'supreme' in its law-making powers. This principle was fundamentally affected when the UK joined the EU in 1973. Parliamentary supremacy meant that: 1) The UK Parliament was able to make UK law as it saw fit either by repealing earlier statutes, over-ruling case law or by making new law. 2) No UK Parliament could bind its successor. Parliament could not make laws that a subsequent Parliament was prevented from altering or repealing. 3) The UK courts had to apply the relevant statute law enacted by the UK Parliament. By joining the EU, UK Parliamentary supremacy was fundamentally affected and it is no longer true to say that only the UK Parliament has the power to make new law for the UK. The effect of becoming a member of the EU was to cede the UK Parliament's supremacy on certain matters of European Union law which have direct effect on member states. The position now is that: 1) The EU may pass legislation directly for the UK. 2) The UK cannot, generally, make laws that conflict with EU law. 3) Overall, EU law enjoys supremacy over domestic national law and is applied in priority to domestic law.