The timeline story of Brexit
2016
June 23: The United Kingdom votes in a referendum to leave the European Union, sparking a political earthquake across Europe. But the result is close: 52 to 48%. A majority of voters in England and Wales have backed "Leave", but Scotland and Northern Ireland have voted "Remain". David Cameron, who led the campaign to remain in the EU, says he will resign as prime minister.
July 11: Theresa May wins the Conservative Party leadership contest and becomes prime minister two days later. “Brexit means Brexit, and we will make a success of it,”
November 3: The UK’s High Court rules that the British government cannot trigger Article 50 without parliamentary approval (a decision later confirmed by the Supreme Court). It provokes the Daily Mail to castigate the judges as “Enemies of the People”
2017
March 29: May sends a letter to European Council President Donald Tusk, triggering Article 50. It sets the date for the UK’s departure in two years’ time: March 29, 2019.
June 8: The Conservatives lose their majority at the general election. May is forced to do a deal with Northern Irish unionists from the DUP to stay in power.
2018
July 6: May unveils to her cabinet her much-awaited Chequers plan, named after the venue, the prime minister’s country residence. It builds on May’s previously outlined policy of “managed divergence” from EU rules. But it suggests a much softer Brexit than earlier statements had suggested, with a “common rulebook” with the EU over goods. The plan is officially published the following week.
November 25: The UK and the EU strike a deal on the UK’s exit terms. It is signed off by leaders of the other EU27 member states at a summit in Brussels – but needs the approval of the UK and European parliaments to take effect. Agreement is sealed after May adapts her Brexit plan to include an all-UK customs union with the EU to resolve the controversial Irish border “backstop”.
2019
January 15: The government loses the first “meaningful vote” in parliament on the Brexit deal, by 432 votes to 202. It marks the worst government parliamentary defeat in the UK’s history.
January 30: The UK parliament gives May a mandate to go back to Brussels to seek “alternative arrangements” to the Irish backstop.
March 12: The government loses the second meaningful vote by 149 votes, after the UK’s attorney-general says a hastily-revised deal does not guarantee that the UK can exit the backstop unilaterally.
March 20: Obliged to do so by parliament, May asks the EU to delay Brexit from March 29 until June 30. The next day EU leaders offer the UK two alternative extensions: to May 22 if the deal is passed, April 12 if it is not.
March 29: The government loses a third meaningful vote on the Brexit deal in parliament, by a margin of 58 votes. However, this period also sees MPs unable to find a majority for any alternative solution – including a second referendum.
July 23: Boris Johnson wins the Tory leadership contest after several weeks of ballots. The following day he enters Downing Street as the UK’s new prime minister.
August 28: The UK Parliament is prorogued, or suspended, for five weeks, upon advice given to Queen Elizabeth II by Boris Johnson’s government.
The Prorogation declared unlawful by the Supreme Court
September 9: The “Benn bill” becomes law, in effect preventing the UK from leaving the EU with no exit deal, without parliament’s consent.
October 17: The UK and EU announce dramatically that they have struck a new Brexit deal, ahead of a Brussels summit. It replaces the Irish backstop, following a compromise which sees the UK in particular make concessions over Northern Ireland.
October 28: The EU agrees to offer the UK a Brexit “flextension” until January 31. The offer is formally approved the next day.
October 29: The House of Commons approves a general election on December 12, lifting previous objections to Boris Johnson’s repeated requests.
December 12: The UK’s general election is won convincingly by Boris Johnson’s Conservatives, who gain an 80-seat majority. But Scotland and Northern Ireland in particular register strong anti-Brexit votes.
2020
January 23: The UK’s EU Withdrawal bill becomes law, after a relatively smooth passage through parliament compared to the earlier havoc.
January 29: The European Parliament approves the Brexit divorce deal.
January 31: The UK officially leaves the EU at midnight CET (11 p.m. UK time).
February 1: An 11-month transition phase begins, running to December 31, 2020. Most arrangements will remain the same but both sides face a race against the clock to sort out the future EU-UK relationship.