United Kingdom membership of the European Union

Part of a series of articles on
UK membership of the European Union (1973–2020)
Accession Treaty of Accession 1972 1972 EC Act 1973 enlargement of the EC
1975 referendum Referendum Act (results)
Treaty amendments Single European Act, 1986 (UK ratification) Maastricht Treaty, 1992 (UK ratification) Treaty of Amsterdam, 1997 (UK ratification) Treaty of Nice, 2001 (UK ratification) Treaty of Lisbon, 2007 (UK ratification) Related: 2011 UK Act on new EU Treaty amendments EU-related British Acts Proposed European Constitution referendum European Union Bill 2004–2005
MEPs for UK constituencies Members 1973–1979 (elected by parliament) Members 1979–1984 (1979 election) Members 1984–1989 (1984 election) Members 1989–1994 (1989 election) Members 1994–1999 (1994 election) Members 1999–2004 (1999 election) Members 2004–2009 (2004 election) Members 2009–2014 (2009 election) Members 2014–2019 (2014 election) Members 2019–2020 (2019 election) Women
Officials and bodies House of Lords EU Committee House of Commons EU Committee Permanent EU Representatives for UK Northern Ireland Executive in Brussels EU Representative in London UK European Commissioners Department for Exiting the European Union
Issues and events Economy The Euro Black Wednesday UK budget rebate Nationality law Euroscepticism in the UK United Kingdom opt-outs from EU legislation Maastricht Rebels Balance of Competences Review
Withdrawal 2015 UK general election 2015–2016 membership renegotiation 2016 EU membership referendum Vote Leave Britain Stronger in Europe Notification of withdrawal 2017 UK general election Brexit negotiations Impact of Brexit Future relationship Withdrawal agreement No-deal Brexit Impact on Irish border Northern Ireland Protocol Parliamentary votes Proposed second referendum 2019 UK general election
EU portal  UK portal
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The United Kingdom (along with the British Overseas Territory of Gibraltar) was a member state of the European Union (EU) and of its predecessor the European Communities (EC) – principally the European Economic Community (EEC) from 1 January 1973 until 31 January 2020. Since the foundation of the EEC, the UK had been an important neighbour and then leading member state, until Brexit ended 47 years of membership. During the UK's time as a member state two referendums were held on the issue of its membership, with the first being held on 5 June 1975, resulting in a vote to stay in the EC, and the second, held on 23 June 2016, which resulted in the vote to leave the EU.