Brexit (United Kingdom)

Brexit (United Kingdom)
Name	United Kingdom and European Union withdrawal
Caption	Union Flag
Date	2016–2020
Location	United Kingdom, European Union

Contents

Brexit (United Kingdom) was the process by which the United Kingdom withdrew from the European Union following a 2016 national referendum and a multi-year political, legal, and diplomatic negotiation culminating in formal departure on 31 January 2020 and transition completion on 31 December 2020. The episode involved leading figures such as David Cameron, Boris Johnson, Theresa May, and institutions including the Parliament of the United Kingdom, the European Commission, the European Council, and the House of Commons, and reshaped relationships with states and organizations like the United States, Canada, China, the United Nations, and the World Trade Organization.

Background

The United Kingdom's membership in the European Economic Community began in 1973 under Edward Heath after negotiations with the EEC and ratification involving the UK Parliament and national politics. Debates over sovereignty had earlier involved figures such as Harold Wilson, the Conservative Party, and the Labour Party, and were influenced by events such as the creation of the Single European Act, the Maastricht Treaty, the Treaty of Lisbon, and rulings by the European Court of Justice. Eurosceptic movements within parties and organizations including the United Kingdom Independence Party, the Referendum Party, and think tanks such as the Adam Smith Institute and the Centre for European Reform pushed for renegotiation or withdrawal, engaging media outlets like the BBC and the Daily Mail.

The 23 June 2016 referendum was held after a pledge by David Cameron and a promise delivered in the Conservative Party manifesto and subsequent renegotiation at a European Council summit led by Donald Tusk. Campaigns included Vote Leave, led by figures such as Boris Johnson and Michael Gove, and Britain Stronger in Europe (often called Remain), supported by Tony Blair, Gordon Brown, George Osborne, and organizations like the Confederation of British Industry and the Trade Union Congress. High-profile interventions came from global leaders, including Barack Obama and Angela Merkel, and institutions like the International Monetary Fund and the Bank of England. The result—52% Leave to 48% Remain—precipitated the resignation of David Cameron and appointment of Theresa May as Prime Minister.

Theresa May triggered Article 50 of the Treaty on European Union on 29 March 2017, beginning a two-year exit negotiation with the European Commission's negotiating team led by Michel Barnier and endorsement by the European Parliament. Talks covered the Withdrawal Agreement, financial settlement with the European Investment Bank implications, citizens' rights referencing the European Court of Justice, and the contentious Northern Ireland backstop later replaced by the Northern Ireland Protocol negotiated under Boris Johnson. Multiple UK Parliament votes, attempts at prorogation contested by the Supreme Court of the United Kingdom, and general elections including the 2017 and 2019 contests featuring leaders Jeremy Corbyn and Jo Swinson shaped the timeline. A revised Withdrawal Agreement and a Political Declaration on future relations were ratified by the House of Commons and the European Council prior to the UK's departure.

Brexit reshaped UK party politics, realigning Conservative factions and precipitating splits in the Labour Party under Jeremy Corbyn. MPs such as Ian Duncan Smith, Jacob Rees-Mogg, Chuka Umunna, and Sajid Javid played notable roles, while figures like Nigel Farage and Caroline Lucas influenced public debate. Devolution issues involved the Scottish National Party, leading to renewed discussion of Scottish independence and interactions with the Scottish Parliament and leaders like Nicola Sturgeon. Northern Ireland tensions invoked the Good Friday Agreement and talks with Irish Government stakeholders including Leo Varadkar and institutions such as the Northern Ireland Assembly and Stormont.

Economic forecasts and outcomes drew on analyses from the Office for National Statistics, the Bank of England, the International Monetary Fund, and think tanks such as the Institute for Fiscal Studies and the National Institute of Economic and Social Research. Sectors affected included finance in the City of London, automotive industries tied to suppliers in Germany, France, and Spain, and fisheries involving Norway and Iceland comparisons. Migration changes affected workers from Poland, Romania, India, and Pakistan, with implications for the National Health Service workforce and higher education ties with institutions like the University of Oxford and the University of Cambridge. Social debates engaged organizations such as Liberty (UK human rights), Amnesty International, and faith bodies including the Catholic Church in the UK.

Post-withdrawal relationships involved negotiating free trade agreements with partners such as the United States, the European Free Trade Association, Canada (building on Comprehensive Economic and Trade Agreement experience), Australia, and Japan, and navigating World Trade Organization rules. The UK sought continuity in security cooperation with NATO, judicial cooperation including Europol arrangements, and continued participation in programs like Horizon Europe and the European Investment Bank dialogue. Diplomatic ties with the Republic of Ireland and the Irish Government were central due to the Northern Ireland Protocol, and wider geopolitical adjustments involved relations with Russia and engagement with multilateral bodies such as the United Nations Security Council.

Domestic legal changes included the enactment of the European Union (Withdrawal) Act 2018 and subsequent statutory instruments to convert EU law into domestic law, addressing supremacy and direct effect issues previously overseen by the European Court of Justice. Institutional adjustments affected agencies such as the Information Commissioner's Office and the Financial Conduct Authority, and international agreements required treaty continuity managed by the FCDO and the Cabinet Office. Devolution settlements prompted legal interactions with the Supreme Court of the United Kingdom and the Judicial Committee of the Privy Council in specific contexts.