Crunch time is coming for British politicians and European Union leaders, who are scrambling to find a way to way to make Brexit work.
Britain is set to leave the EU on April 12 without an agreement in place unless a plan is reached or a further extension is granted.
British politicians are deeply divided over a solution and EU leaders are exasperated by the slow pace of progress.
Some possible scenarios for what might happen next in the coming days.
If Britain can't break the impasse, it risks crashing out of the EU without a deal.
Last month, the EU agreed to postpone the March 29 departure date, but gave Britain only until April 12 to pass Prime Minister Theresa May's original agreement, come up with a new plan and seek a further extension, or leave without an agreement or a transition period to smooth the way. On Friday, May requested a further extension until June 30.
Most politicians, economists and business groups think that leaving the world's largest trading bloc without an agreement would be damaging for the EU and disastrous for the U.K. It could lead to tariffs on trade between Britain and the EU, as well as customs checks that could cause gridlock at ports and shortages of essential goods.
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A hardcore of pro-Brexit lawmakers in May's Conservative Party dismiss such warnings as fear-mongering. But most oppose leaving without a deal. Parliament has voted repeatedly to rule out a "no-deal" Brexit.
A no-deal Brexit is still the legal default position, however, and it could happen if the EU refuses to grant another extension. The bloc says it will only agree to delay Brexit if Britain breaks its impasse and comes up with a new plan.
With so much at stake, and so little time, there are at least two ways in which Britain might find a compromise solution that gains majority support in its deeply divided Parliament.
First would be a breakthrough in ongoing negotiations between the odd couple of May and opposition Labour Party leader Jeremy Corbyn. If May can gain Corbyn's support, he could shift the parliamentary math in her favor and a deal could likely be agreed.
Few are holding out hope for this outcome, in part because it would probably require May to dramatically alter some of her long-held positions and embrace a much softer version of Brexit. Indeed, Labour's Brexit spokesman, Keir Starmer, said Friday after three days of talks that the government is not showing any willingness to change its approach and find common ground.
A second possibility revolves around May's promise to hold a series of "indicative votes" in Parliament if her talks with Corbyn are unsuccessful. These votes would gauge Parliament's sentiment for getting a majority behind a version of Brexit.
May has said the government would abide by any such vote, but it is not clear when — and how — these votes would be held.
If Britain's warring factions don't agree on a way forward, European Council President Donald Tusk is urging a Brexit delay of up to one year, but with built-in flexibility to let Britain leave earlier if it has an agreement in place.
This approach has been dubbed the "flextension" in yet another addition to the crowded and sometimes confusing glossary of Brexit-related terms. Tusk hopes to get this option approved at an EU summit on Wednesday.
A "flextension" is not exactly what May is seeking; she wants a shorter delay. If Britain stays for another year, it would have to take part in European Parliament elections set for late next month.
Having Britain participate in the balloting would be required to protect the integrity of the European election process, but it would tie the U.K. closer to the EU at a time when politicians are trying to finalize the country's divorce from the rest of the bloc.
A year-long extension might well please the many Britons who hope Brexit never takes place, and it is likely to enrage Brexit-backers who fear their victory in the 2016 referendum is being hollowed out by endless slowdowns and concessions.
BACK TO THE BALLOT BOX?
Parliament already has narrowly rejected a proposal for a new referendum on whether to leave the EU, and the government has ruled out holding another plebiscite, saying voters in 2016 made their decision to leave.
But with divisions in both Parliament and in May's Cabinet, handing the decision back to the people in new balloting might be seen as the only way forward.
A proposal for any Brexit deal to be put to a public vote in a "confirmatory referendum" was backed by opposition parties, as well as some of May's Conservatives.
At least one prominent Cabinet member, Treasury chief Philip Hammond, says such a proposal might have merit.