The United Kingdom officially left the European Union on 31 January 2020, after 47 years of membership. The UK had been a member of the EU since 1 January 1973. The decision to leave the EU was made in a referendum held on 23 June 2016, in which 52% of voters voted to leave. The UK’s withdrawal from the EU was a complex and controversial process, which was marked by political and economic uncertainty. The UK’s relationship with the EU after Brexit is still being negotiated.