- Britain votes to leave -
In a June 23, 2016 referendum Britons choose to leave the 28-nation EU by a narrow 52 percent to 48 percent. Conservative prime minister David Cameron, who led the campaign to remain in the EU, resigns.
- May becomes prime minister -
May, the remain-backing interior minister, becomes prime minister on July 13. On January 17, 2017 she sets out her Brexit strategy, saying Britain will leave Europe's single market to allow it to control EU immigration.
"No deal for Britain is better than a bad deal," she insists.
- Exit process triggered -
On March 13, 2017 Britain's parliament approves a bill empowering May to trigger the EU process for leaving the union.
With a letter to the EU Council formally announcing Britain's intention to leave, the government starts a two-year timetable for withdrawal by March 29, 2019.
- Lost majority -
To strengthen her hand in Brexit negotiations, May calls a snap election for June 8, 2017. Her Conservatives lose their parliamentary majority and are forced to strike a deal for support from Northern Ireland's Democratic Unionist Party.
- Top ministers quit -
On July 6, 2018 May wins agreement from her warring cabinet to pursue "a UK-EU free trade area" and strong alignment with the EU after Brexit.
Two days later Eurosceptic Brexit minister David Davis quits, saying May is giving "too much away too easily". Foreign minister Boris Johnson follows suit on July 9.
- Draft deal agreed -
On November 13 British and EU negotiators reach a draft divorce agreement, which May's cabinet backs the following day after heated debate.
But four ministers, including new Brexit secretary Dominic Raab, resign. EU leaders approve the accord on November 25. "This is the only deal possible," insists European Commission President Jean-Claude Juncker.
May faces a furious backlash from her own party. On December 12 Conservative MPs hold a no-confidence vote but she survives, winning by 200 to 117.
- British MPs reject deal -
In the first parliament vote on the deal on January 15, 2019, MPs are 432 to 202 against -- the worst defeat for a government in modern British political history.
It is rejected again on March 12. Main opposition Labour leader Jeremy Corbyn calls a vote of no confidence in the government on January 16.
It survives by 325 to 306 votes, as May's Conservatives rally round.
- Brexit delay -
With Britain making no headway in finalising its departure deal, the EU on March 21 agrees to a delay but says Britain must outline a plan by April 12 or face a no-deal Brexit.
- May's resignation pledge -
In a dramatic meeting with fellow Conservatives on March 27, May promises to resign if her main leadership rivals support her deal and help it over the line.
Parliament still rejects the deal on March 29 for the third time.
May reaches out to the Labour Party for a compromise deal to get the Brexit deal through parliament.
She gives the go-ahead for Britain to take part in European Parliament elections on May 23.
- Six-month delay -
EU leaders agree on April 11 to delay Brexit by up to six months. In early May Conservatives lose hundreds of seats at local elections.
On May 17 the Labour opposition pulls out of talks on a compromise.
- May resigns -
In last-gasp effort to get a deal through parliament, May promises on May 21 to give lawmakers a vote on whether to hold a second Brexit referendum. It prompts a furious reaction among Conservatives.
May announces on May 24 she will step down as Conservative leader on June 7, making way for the election of a new prime minister.
The EU says her resignation changes nothing in the Brexit talks.