Proposed referendum on United Kingdom membership of the European Union

United Kingdom European Union membership referendum
Should the United Kingdom remain a member of the European Union or leave the European Union?
Location	United Kingdom Gibraltar
Date	23 June 2016
Results Votes  % Leave 17,410,742 7001518900000000000♠51.89% Remain 16,141,241 7001481100000000000♠48.11% Valid votes 33,551,983 7001999200000000000♠99.92% Invalid or blank votes 25,359 6998800000000000000♠0.08% Total votes 33,577,342 100.00% Registered voters/turnout 46,500,001 7001722109999999999♠72.21%
Results by voting areas   Leave     Remain
On the map, the darker shades for a colour indicate a larger margin.

The United Kingdom European Union membership referendum, also known as the EU referendum and the Brexit referendum, took place on 23 June 2016 in the United Kingdom (UK) and Gibraltar to gauge support for the country either remaining a member of, or leaving, the European Union (EU). The referendum resulted in 51.9% of voters voting in favour of leaving the EU. The government initiated the official EU withdrawal process on 29 March 2017, which put the UK on course to complete the withdrawal process by 30 March 2019.

Membership of the EU and its predecessors has long been a topic of debate in the United Kingdom. The country joined what were then the three European Communities, principally the European Economic Community (EEC, or "Common Market"), in 1973. A first referendum on continued membership of the then European Communities (Common Market) was held in 1975, and it was approved by 67.2% of "Yes" voters compared to 32.8% of "No" voters.

In May 2015, in accordance with a Conservative Party manifesto commitment following that party's surprise victory in the 2015 UK general election, the legal basis for a referendum on EU membership was established by the UK Parliament through the European Union Referendum Act 2015. Britain Stronger in Europe was the official group campaigning for the UK to remain in the EU, and was endorsed by the Prime Minister David Cameron and Chancellor George Osborne. Vote Leave was the official group campaigning for the UK to leave the EU, and was fronted by the Conservative MP Boris Johnson, Secretary of State for Justice Michael Gove and Labour MP Gisela Stuart. Other campaign groups, political parties, businesses, trade unions, newspapers and prominent individuals were also involved, and each side had supporters from across the political spectrum.