After a shrill referendum campaign, nearly 52% of British voters opted to leave the EU on June 23. Polls had shown a close race before the vote with a slight lead for those favoring remaining in the EU. Conservative British Prime Minister David Cameron, who had campaigned for Britain to stay, acknowledged the "will of the British people" and resigned the following morning.

Former Home Secretary Theresa May replaced David Cameron as prime minister on July 11 and promised the country that "Brexit means Brexit." May had quietly supported the Remain campaign before the referendum. She did not initially say when her government would trigger Article 50 of the EU treaty to start the two-year talks leading to Britain's formal exit.

May eventually signed a diplomatic letter over six months later on March 29, 2017 to trigger Article 50. Hours later, Britain's ambassador to the EU, Tim Barrow, handed the note to European Council President Donald Tusk. Britain's exit was officially set for March 29, 2019. Tusk ended his brief statement on the decision with: "We already miss you. Thank you and goodbye."

British Brexit Secretary David Davis and the EU's chief negotiator, Michel Barnier, kicked off talks in Brussels on June 19. The first round ended with Britain reluctantly agreeing to follow the EU's timeline for the rest of the negotiations. The timeline split talks into two phases. The first would settle the terms of Britain's exit, and the second the terms of the EU-UK relationship post-Brexit.

The second round of talks in mid-July began with an unflattering photo of a seemingly unprepared British team. It and subsequent rounds ended with little progress on three phase one issues: How much Britain still needed to pay into the EU budget after it leaves, the post-Brexit rights of EU and British citizens and whether Britain could keep an open border between Ireland and Northern Ireland.

Leaders of the remaining 27 EU members formally agreed that "sufficient progress" had been made to move on to phase two issues: the post-Brexit transition period and the future UK-EU trading relationship. While Prime Minister Theresa May expressed her delight at the decision, European Council President Tusk ominously warned that the second stage of talks would be "dramatically difficult."

British ministers appeared to back a Brexit plan at May's Chequers residence on July 6. The proposal would have kept Britain in a "combined customs territory" with the EU and signed up to a "common rulebook" on all goods. That went too far for British Foreign Minister Boris Johnson and Brexit Secretary David Davis, who resigned a few days later. May replaced them with Jeremy Hunt and Dominic Raab.

May's Chequers proposal did not go down well with EU leaders, who told her at a summit in Salzburg in late September that it was unacceptable. EU Council President Tusk trolled May on Instagram, captioning a picture of himself and May looking at cakes with the line: "A piece of cake perhaps? Sorry, no cherries." The gag echoed previous EU accusations of British cherry-picking.

EU leaders endorsed a 585-page draft divorce deal and political declaration on post-Brexit ties in late November. The draft had been widely condemned by pro- and anti-Brexit lawmakers in the British Parliament only weeks earlier. Brexit Secretary Dominic Raab resigned along with several other ministers, and dozens of Conservative Party members tried to trigger a no-confidence vote in May.

In the face of unrelenting opposition, May postponed a parliamentary vote on the deal on December 10. The next day, she met with German Chancellor Angela Merkel to seek reassurances that would, she hoped, be enough to convince skeptical lawmakers to back the deal. But while she was away, hard-line Conservative lawmakers triggered a no-confidence vote. May won the vote a day later.

The UK Parliament voted 432 to 202 against May's Brexit deal on January 16. In response to the result, European Council President Donald Tusk suggested the only solution was for the UK to stay in the EU. Meanwhile, Britain's Labour Party called for a no-confidence vote in the prime minister, her second leadership challenge in as many months.

May tried to get legal changes to the deal's so-called Irish backstop in the weeks that followed. She eventually got assurances that the UK could suspend the backstop under certain circumstances. But on March 12, Parliament voted against the revised Brexit deal by 391 to 242. EU leaders warned the vote increased the likelihood of a no-deal Brexit. Two days later, MPs voted to delay Brexit.

Following the second defeat of May's divorce deal, the European Council met in Brussels on March 21 to decide what to do next. EU leaders gave May two options: delay Brexit until May 22 if MPs vote for the withdrawal deal or delay it until April 12 if they vote against the deal. If the deal were to fail again in Parliament, May could ask for a long extension.

On March 29, the day that the UK was supposed to leave the EU, British lawmakers voted for a third time against May's deal — rejecting it this time with a vote of 344 to 286. Following the latest defeat, May approached the main opposition Labour leader Jeremy Corbyn in an attempt to find a compromise, angering hardline Brexiteers in her own Conservative party.

With the April 12 deadline looming after the third defeat of May's deal, EU leaders met again in Brussels to discuss a second delay. The only question was how long should it be? In the end, the UK and EU agreed to a "flexible" extension until October 31 — which can end sooner if the Brexit deal is approved. The UK had to take part in EU elections in May because their exit wasn't secured in time.

Weeks of talks between Prime Minister Theresa May and the Labour party to reach a deal proved unsuccessful and further eroded her political capital. She triggered an angry backlash from her party after she tried to put the option of a second referendum on the table. The series of failures led May to announce her resignation, effective June 7, in an emotional address.

After Theresa May announced on June 7 that she would leave office, other members of her Conservative party began clamoring for the top job. Within a month, the leadership battle came down to Jeremy Hunt (left), an EU proponent who fears a no-deal scenario, and Boris Johnson (right), one of the main proponents of Brexit.

At the end of July 2019, Johnson was officially named Theresa May's successor as British prime minister. "We are going to energize the country, we are going to get Brexit done by October 31," he said after he was elected leader of the Conservative Party.

Conservative rebels and opposition MPs backed efforts to delay an October 31 Brexit deadline in fear of a no-deal departure. In response, Johnson called for a general election, saying his government cannot rule without a mandate after he stripped 21 rebel MPs of their Conservative status. The Labour Party said it would not back elections until legislation to block a no-deal Brexit was in place.

In late September, Britain's highest court ruled that Johnson's decision to suspend Parliament ahead of the UK's planned exit was unlawful. "This was not a normal prorogation in the run-up to a Queen's Speech," said the Supreme Court. Political rivals immediately called on Johnson to leave his post. Johnson said he would abide by the court ruling, though said he "strongly" disagreed.

British Prime Minister Boris Johnson managed to secure a deal with European negotiators that would allow the UK to leave the EU in an orderly manner. The deal received unanimous backing from the leaders of 27 other member states. But an attempt to get the UK Parliament to sign off on the deal failed. Instead, Parliament pushed for the Brexit deadline to be extended until the end of January 2020.

On December 22, UK lawmakers vote for Prime Minister Johnson's European Union withdrawal bill, which will see a leave date of January 31 2020 enshrined in law. Getting a majority to vote to pass the bill in the lower house has proven a major sticking point for the PM, but following a general election Johnson's Conservative party won control of the house and the bill passed with a 124 majority.

After months of disagreements over fishing rights and future business rules, the EU and UK clinched a post-Brexit trade deal on Christmas Eve. Prime Minister Boris Johnson hailed the deal, saying the UK has "taken back control of our laws and our destiny." The deal will allow the UK and the EU to trade without tariffs, but also impose limitations on free movement and financial services.

May became prime minister after David Cameron resigned from the post in the wake of the Brexit referendum vote in June 2016. Despite her position, she has struggled to define what kind of Brexit her government wants. Hardliners within her Conservative party want her to push for a clean break. Others want Britain to stay close to the bloc. The EU itself has rejected many of May's Brexit demands.

The leader of the British Labour Party has no formal role in the Brexit talks, but he is influential as the head of the main opposition party. Labour has tried to pressure the Conservative government, which has a thin majority in Parliament, to seek a "softer" Brexit. But Corbyn's own advocacy has been lukewarm. The long-time leftist voted for the UK to leave the European Community (EC) in 1975.

Boris Johnson's turbulent two years as UK foreign secretary came to an abrupt end with his resignation on July 9. The conservative had been a key face for the Leave campaign during the 2016 referendum campaign. Johnson disapproves of the "soft Brexit" sought by PM May, arguing that a complete break from the EU might be preferable. He became the second Cabinet member within 24 hours to quit...

David Davis headed Britain's Department for Exiting the EU and was the country's chief negotiator in the talks before he quit on July 8, less than 24 hours before Downing Street announced Boris Johnson's departure. Davis had long opposed Britain's EU membership and was picked for the role for this reason. Davis was involved in several negotiating rounds with his EU counterpart, Michel Barnier.

Raab replaced Davis in early July 2018. But he only lasted four months, resigning a day after Theresa May presented a draft withdrawal plan to her cabinet. Raab previously worked for a Palestinian negotiator in the Oslo peace process and as an international lawyer in Brussels advising on European Union and World Trade Organization law.

Jeremy Hunt was Britain's Health Secretary until he replaced Boris Johnson as foreign secretary in early July 2018. The 51-year-old supported Britain remaining in the European Union during the 2016 referendum, but said in late 2017 that he had changed his mind in response to the "the arrogance of the EU Commission" during Brexit talks. He has vowed to help get Britain a "great Brexit deal."

Nigel Farage was the leader of the United Kingdom Independence Party (UKIP) until July 2016. Under his stewardship, the party helped pressure former Prime Minister David Cameron into calling the EU referendum. He was also a prominent activist in the Leave campaign in the lead-up to the vote. Farage still has some influence over Brexit talks due to his popularity with pro-Leave voters.

Businessman Arron Banks is a friend of Nigel Farage, and donated a significant sum to the former UKIP leader's Leave.EU campaign – making him the group's biggest financial backer. He had several meetings with Russian officials ahead of the referendum, but has denied allegations of collusion with Moscow in the Brexit vote, branding the claims a "political witch hunt."

EU Commission President Juncker (left) and EU Council President Tusk (right) share two of the bloc's highest posts. Juncker heads the EU's executive. Tusk represents the governments of the 27 EU countries — the "EU 27." Both help formulate the EU's position in Brexit negotiations. What Tusk says is particularly noteworthy: His EU 27 masters — not the EU commission — must agree to any Brexit deal.

The former French foreign minister and European commissioner has become a household name across the EU since his appointment as the bloc's chief Brexit negotiator in October 2016. Despite his prominence, Barnier has limited room to maneuver. He is tasked with following the EU 27's strict guidelines and must regularly report back to them during the negotiations.

The Irish PM has been one of the most important EU 27 leaders in Brexit talks. Britain has said it will leave the EU's customs union and single market. That could force the Republic of Ireland, an EU member, to put up customs checks along the border with Northern Ireland, a British province. But Varadkar's government has repeatedly said the return of a "hard" border is unacceptable.

The leaders of the EU 27 governments have primarily set the EU's negotiating position. They have agreed to the negotiating guidelines for chief negotiator Barnier and have helped craft the common EU position for Tusk and Juncker to stick to. The individual EU 27 governments can also influence the shape of any Brexit outcome because they must unanimously agree to a final deal.