Timeline: Brexit explained in ten key dates

Authorised in 2015 and staged the next year, the Brexit referendum is still shaping British history

British Prime Minister Theresa May leaves after addressing a media conference at an EU summit in Brussels. AP

The issue of Britain in Europe has divided British politics for more than five decades. The turning point came when the country held a second referendum on leaving the bloc – the first was in 1975 – in 2016. The surprise vote to leave has resulted in some of the most tumultuous events ever seen in politics. Here is timeline of how the crisis has played out:

17 December 2015: The European Union Referendum Act receives Royal Assent, allowing for a referendum to be held on whether the UK should remain a member of the EU. Prime Minister David Cameron had vowed to hold an in-out referendum but campaigned to remained in the European Union.

23 June 2016: A referendum is held and 51.9 per cent of the population votes to leave the EU.

24 June 2016: David Cameron announces his resignation as Prime Minister and is replaced by Theresa May in July.

29 March 2017: The UK government invokes Article 50 of the Treaty on European Union, effectively triggering the exit process from the European Union. This gives the UK two years to negotiate an exit deal with the EU.

15 January 2019: The House of Commons votes against a Draft Withdrawal Agreement published in November 2018 by a margin of 432 to 202, the largest parliamentary defeat in UK history.

12 March 2019: The House of Commons rejects the draft agreement a second time with a margin of 391 to 242.

21 March 2019: The European Council offers to extend the Article 50 period until 22 May 2019 if the Withdrawal Agreement is passed by 29 March 2019 but, if it does not, then the UK has until 12 April 2019 to indicate a way forward. The extension is formally agreed the following day.

29 March 2019: The original end of the Article 50 period and the original planned date for Brexit. The UK Government is defeated again by 344 votes to 286 and the Withdrawal Agreement is rejected.

10 April 2019: The European Council grants another extension to the Article 50 period to 31 October 2019, or the first day of the month after that in which the Withdrawal Agreement is passed.

24 May 2019: Mrs May announces she will stand down as Conservative leader on June 7.

Watch: May's exit leaves Brexit in doubt