The United Kingdom joined what was then the European Economic Community (EEC), later known as the European Union, on 1 January 1973.

Key date

  • Official accession date: 1 January 1973.
  • The accession followed the signing and ratification of the Treaty of Accession in 1972 under Prime Minister Edward Heath.

Extra context

  • The UK had earlier applications to join in the 1960s that were vetoed by France before finally being accepted and admitted in 1973.
  • The EEC later evolved into the modern European Union, so references to the UK “joining the EU” typically point to this 1973 entry into the European Communities.

TL;DR: The UK joined on 1 January 1973, entering the European Communities that later became the EU.

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