Brexit

Brexit (/ˈbrɛksɪt, ˈbrɛɡzɪt/; a portmanteau of "Britain" and "Exit") was the withdrawal of the United Kingdom (UK) from the European Union (EU).

Brexit officially took place at 23:00 GMT on 31 January 2020 (00:00 1 February 2020 CET). The UK, which joined the EU's precursor, the European Communities (EC), on 1 January 1973, is the only member state to have withdrawn from the EU, although previously the territories of Algeria (formerly part of France) left in 1976 and Greenland (part of the Kingdom of Denmark) left the EC in 1985. Following Brexit, EU law and the Court of Justice of the European Union no longer have primacy over British laws but the UK remains legally bound by obligations in the various treaties it has with other countries around the world, including many with EU member states and indeed with the EU itself. The European Union (Withdrawal) Act 2018 retains relevant EU law as domestic law, which the UK can amend or repeal.

The EU and its institutions developed gradually after their establishment. Throughout the period of British membership, Eurosceptic groups had existed in the UK, opposing aspects of the EU and its predecessors. The Labour Prime Minister Harold Wilson's pro-EC government held a referendum on continued EC membership in 1975, in which 67.2% voted to stay within the bloc. Despite growing political opposition by a minority of UK politicians to further European integration aimed at "ever closer union" between 1975-2016, notably from factions of the Conservative Party in the 1980s-2000s, no further referendums on the issue were held.

By the mid-2010s, the growing popularity of the UK Independence Party (UKIP), as well as pressure from Eurosceptics within his own party, persuaded the Conservative Prime Minister David Cameron to promise a referendum on British membership of the EU if his government was re-elected. Following the 2015 general election, which produced a small but unexpected majority for the governing Conservative Party, the promised referendum on continued EU membership was held on 23 June 2016. Notable supporters of the Remain campaign included then-Prime Minister David Cameron, the future Prime Ministers Theresa May, Liz Truss, and Sir Keir Starmer, and the ex–Prime Ministers John Major, Tony Blair, and Gordon Brown; notable supporters of the Leave campaign included the future Prime Ministers Boris Johnson and Rishi Sunak. The electorate voted to Leave the EU and obtained this result with a slight margin, with a 51.9% share of the vote, all regions of England and Wales except London voting in favour of Brexit, and Scotland and Northern Ireland voting to Remain. The result led to Cameron's sudden resignation, his replacement by former Home Secretary Theresa May, and four years of negotiations with the EU on the terms of departure and on future relations, completed under a Boris Johnson-led government, with the Conservative Party in office during this period.

The negotiation process was both politically challenging and deeply divisive within the UK, leading to two snap general elections in 2017 and 2019. One proposed deal under the Second May ministry was overwhelmingly rejected by the UK Parliament, causing great uncertainty and leading to postponement of the withdrawal date to avoid a no-deal Brexit. The UK officially left the European Union on 31 January 2020 after a withdrawal deal was passed by Parliament, but continued to participate in many EU institutions (including the single market and customs union) during an eleven-month transition period during which it was hoped that details of the post-Brexit relationship could be agreed and implemented. Trade deal negotiations continued within days of the scheduled end of the transition period, and the EU–UK Trade and Cooperation Agreement was signed on 30 December 2020. The effects of Brexit in the UK are in part determined by the cooperation agreement, which provisionally applied from 1 January 2021, until it formally came into force on 1 May 2021.

Following a UK-wide referendum on 23 June 2016, in which 51.89 per cent voted in favour of leaving the EU and 48.11 per cent voted to remain a member state, David Cameron resigned as Prime Minister. On 29 March 2017, the new British government led by Theresa May chose to formally notify the EU of the country's intention to withdraw from the EU in two years, despite there being no agreement among UK politicians on objectives for post-Brexit relations with the EU. The withdrawal, originally scheduled for 29 March 2019, was subsequently delayed by the deadlock in the British parliament after the June 2017 general election, which resulted in a hung parliament in which the Conservatives lost their majority but remained the largest party. This deadlock eventually led to three extensions of the UK's Article 50 process.

The deadlock was resolved after a subsequent general election was held in December 2019. In that election, Conservatives who campaigned in support of a "hard-brexit" withdrawal agreement led by Boris Johnson won an overall majority of 80 seats. After the December 2019 election, the British parliament finally ratified the withdrawal agreement with the European Union (Withdrawal Agreement) Act 2020. The UK left the EU at the end of 31 January 2020 CET (11 p.m. GMT). This began a transition period that ended on 31 December 2020 CET (11 p.m. GMT), during which the UK and EU negotiated their future relationship. During the transition, the UK remained subject to EU law and remained part of the European Union Customs Union and the European single market. However, it was no longer part of the EU's political bodies or institutions.

The withdrawal had been advocated by mostly right-wing and conservative hard Eurosceptics and opposed by pro-Europeanists mostly from the rest of the political spectrum. In 1973, the UK joined the European Communities (EC) – principally the European Economic Community (EEC) – and its continued membership was endorsed in the 1975 membership referendum. In the 1970s and 1980s, withdrawal from the EC was advocated mainly by the political left, e.g. in the Labour Party's 1983 election manifesto. The 1992 Maastricht Treaty, which founded the EU, was ratified by the British parliament in 1993 but was not put to a referendum. The Eurosceptic wing of the Conservative Party led a rebellion over the ratification of the treaty and, with the UK Independence Party (UKIP) and the cross-party People's Pledge campaign, then led a collective campaign, particularly after the Treaty of Lisbon was also ratified by the European Union (Amendment) Act 2008 without being put to a referendum following a previous promise to hold a referendum on ratifying the abandoned European Constitution, which was never held. After promising to hold a second membership referendum if his government was elected, Conservative prime minister David Cameron held this referendum in 2016. Cameron, who had campaigned to remain, resigned after the result and was succeeded by Theresa May.