The United Kingdom left the EU on 31 January 2020 because a majority of voters, 51.9%, chose to leave in a referendum held on 23 June 2016. Leave voters most often cited the principle that decisions about the UK should be taken in the UK, followed by control over immigration.
The United Kingdom joined the European Economic Community in 1973. Its membership was debated throughout the following decades, and in a speech on 23 January 2013 Prime Minister David Cameron said that “democratic consent for the EU in Britain is now wafer thin” and promised a referendum after renegotiating the UK’s relationship with the EU. The referendum took place on 23 June 2016. A majority of 51.9% voted to leave.
Cameron, who had campaigned to remain, announced his resignation the next day. His successor, Theresa May, formally notified the European Council of the UK’s intention to leave on 29 March 2017, under Article 50 of the Treaty on European Union, which sets out how a member state can withdraw. After long negotiations, the Withdrawal Agreement entered into force and the UK left the EU on 31 January 2020. A transition period, during which EU rules still applied, ended on 31 December 2020. Since 1 January 2021, relations have been governed by the Trade and Cooperation Agreement.
Example
Why people voted as they did is best known from surveys. In a poll of 12,369 people interviewed on referendum day, published by Lord Ashcroft Polls on 24 June 2016, 49% of Leave voters said their main reason was “the principle that decisions about the UK should be taken in the UK”. A third (33%) said leaving offered the best chance to regain control over immigration and borders, 13% said that remaining would mean having no choice about how the EU expanded its membership or its powers, and 6% expected economic and trade benefits. Among Remain voters, 43% gave as their main reason that the risks of leaving looked too great for the economy, jobs and prices.
Debates and limits
The meaning of the result remains debated. Leave supporters present it as a vote for sovereignty and democratic control. Remain supporters stress how close it was and how divided the country was: in the same poll, 73% of voters aged 18 to 24 chose Remain, while 60% of those aged 65 and over chose Leave. Polls measure stated reasons, not all the causes of a vote, and their findings are interpreted differently by each side. The Northern Ireland border was one of the most difficult issues of the negotiations: the Withdrawal Agreement includes a protocol on Ireland and Northern Ireland, adjusted in 2023 by the Windsor Framework, to avoid a hard border on the island of Ireland.