Brexit was the withdrawal of the United Kingdom (UK) from the European Union (EU) at 23:00 GMT on 31 January 2020. The UK is the first and only sovereign country to have left the EU. The UK had been a member state of the EU and its predecessor the European Communities (EC) since 1 January 1973. Following Brexit, EU law and the Court of Justice of the European Union no longer have primacy over British laws, except in select areas in relation to Northern Ireland. The European Union (Withdrawal) Act 2018 retains relevant EU law as domestic law, which the UK can now amend or repeal. Under the terms of the Brexit withdrawal agreement, Northern Ireland continues to participate in the European Single Market in relation to goods, and to be a
de facto member of the EU Customs Union.