Brexit

Brexit, a blend of "Britain" and "exit", is the name given to the United Kingdom's departure from the European Union. After voters chose to leave in a referendum on 23 June 2016, the country formally left at 11 p.m. British time on 31 January 2020, after almost half a century of membership, and its new relationship with the EU took effect at the start of 2021. The UK is the only member state ever to have withdrawn, and the process dominated British politics for four years.

Britain joined the European Communities, the forerunner of the EU, on 1 January 1973, and in a 1975 referendum 67.2 per cent of voters backed staying in. Opposition to membership never disappeared. In the 1970s and 1980s it came mainly from the political left, and later chiefly from Eurosceptic Conservatives, who rebelled over the Maastricht Treaty that created the EU in 1992, and from the UK Independence Party. By the mid-2010s UKIP's rising support and pressure within his own party persuaded David Cameron, the Conservative prime minister, to pledge a vote on membership should his party win the 2015 general election, which it did.

Cameron negotiated changes to Britain's membership terms and campaigned to remain; prominent supporters of leaving included the Conservative Boris Johnson. On 23 June 2016, 51.89 per cent voted Leave and 48.11 per cent Remain. England and Wales voted to leave, except for London, while Scotland, Northern Ireland and Gibraltar voted to remain. Cameron resigned and was succeeded in July 2016 by Theresa May.

On 29 March 2017 May's government formally notified the EU of the UK's intention to leave under Article 50 of the EU treaties, starting a two-year countdown. A snap election in June 2017 cost the Conservatives their majority. In November 2018 the two sides agreed a withdrawal agreement, including a financial settlement and a "backstop" designed to avoid a hard border in Ireland, a central concern for the Good Friday Agreement. Parliament rejected the deal three times: by 432 votes to 202 in January 2019, the heaviest defeat ever suffered by a British government, then in March twice more. The leaving date was postponed from 29 March 2019, first to April, then to 31 October and finally to 31 January 2020.

May resigned and Boris Johnson became prime minister on 24 July 2019. In October he agreed a revised deal with the EU in which a Northern Ireland Protocol replaced the backstop. Unable to get it through Parliament, he called an early election for 12 December 2019, in which the Conservatives won an overall majority of 80 seats on a promise to complete the withdrawal. Parliament then passed the European Union (Withdrawal Agreement) Act 2020, the European Parliament gave its consent on 29 January by 621 votes to 49, and the UK left two days later.

During a transition period lasting until the end of 2020, the UK stayed in the EU single market and customs union but had no say in EU decisions. Negotiators reached a Trade and Cooperation Agreement on 24 December 2020, which Parliament approved on 30 December and which applied provisionally from 1 January 2021. The arrangements for Northern Ireland, which kept it closely aligned with EU rules for goods and required checks on goods arriving from Great Britain, remained a source of political dispute.

Assessing the consequences has been a long-running subject of study. Many economists expected Brexit to reduce British income per person over the medium and long term, and studies found that uncertainty after the vote held back investment and trade, while pro-Brexit politicians pointed to new trade agreements with countries such as Canada, Australia and New Zealand, which economists judged far less valuable than EU membership. Since departure, EU law no longer takes precedence over British law, though much of it was kept as domestic law that Parliament can amend or repeal.

Brexit did not change any national borders. Our 2010 map shows the United Kingdom and Ireland as they were during the final decade of British membership.