Dec. 8, 2017: The UK and the European Union reached a significant milestone in their pursuit of a Brexit deal, breaking a deadlock that allows talks to move on to a crucial second phase.
Crucially, the two sides reached a deal on the historically sensitive issue of the Irish border, which had threatened to derail the talks as they reached a critical juncture. Discussions can now move on to the potentially tougher issue of a future trading relationship between the UK and the EU.
Sept. 22, 2017: British Prime Minister Theresa May proposed a "strictly time-limited" transition period to ease Britain's 2019 withdrawal from the European Union. The length of the transition should be determined by how long it takes to work out new arrangements, May said, but "considerations point to an implementation period of around two years." The transition period would give the two sides "access to one another's markets on existing terms," she said.
July 20, 2017: The second round of Brexit talks concluded with a demand from the European Union that Britain clarify its position on key issues. Chief EU negotiator Michel Barnier said more details were needed on how Britain hoped to settle its financial obligations to the bloc and deal with the border between Northern Ireland (part of the U.K.) and the Republic of Ireland, an EU member state. Pictured is Barnier.
June 19, 2017: Formal negotiations regarding Brexit begin. Powerful EU leaders say there is still opportunity for the UK to change its mind and remain in the European Union.
April 19: Members of the British Parliament have approved Prime Minister Theresa May's plan to hold an early general election on June 8. May made a unexpected announcement that she would seek a "snap" election less than halfway through her government's five-year term, with the aim of gaining a stronger mandate for the country's historic withdrawal from the European Union.
On March 29, 2017, the UK government formally served divorce papers on the European Union, signaling the beginning of the end of a relationship that has endured for 44 years.
Theresa May, the British Prime Minister, confirmed that the UK has triggered Article 50 of the Lisbon Treaty, beginning a legal process that must end in two years' time with Britain leaving the EU.
The triggering of Article 50 starts the clock ticking on two years of talks between May's government and the EU, which will involve everything from deals on trade, migration, education and healthcare.
The EU is the UK's biggest trading partner, and experts have warned that striking a comprehensive trade deal in two years will be unlikely. The two parties can, however, continue trade talks beyond this period.
The UK is the first bona fide country to leave. The closest thing prior to this is when Greenland, which is part of Denmark, left in 1985. (The rest of Denmark stayed.) Greece has thought seriously about it though. That would be Grexit (another story altogether). But think about the precedent it sets. With the UK's decision to leave, other EU countries might start eyeing the door too and that'll have huge consequences for the economy and stability. Jan Techau, director of foreign policy think tank Carnegie Europe, said the EU is sure to play hardball when it comes to negotiating the UK's exit.
Even if some terms of divorce are not agreed, the UK will fall out of the union on March 29, 2019. They can split earlier if both parties agree.