Poll: When will the UK leave the EU? Have your say
Theresa May and EU leaders have agreed another extension to Article 50, following the UK Parliament's inability to agree on a deal with the EU.
This means that, provided the UK fights the European elections in May, parliament has until 31 October this year to pass Theresa May's withdrawal agreement.
However, despite the deal having been defeated three times in parliament already and every other option also not receiving parliamentary backing, there is no guarantee that the UK will leave the EU by Halloween.
The crucial dates
1 June: The Prime Minister will have to accept to fight the European elections in May, or the UK could leave without a deal on this date. No deal has also been rejected by parliament.
30 June: This was Theresa May's most recent red line. Speaking in the House of Commons, she said she would not want to see Brexit go undelivered past this date. If she is still in power by this point, the PM could force a vote in the hope she will deliver on her promise.
31 October: The new deadline from the EU following five hours of talks on 10 April. Much like 29 March and 12 April, there is no guarantee it is a hard date but it is the next date for no deal, if the UK fights European elections.
2019: Much could happen in the rest of this year. The Prime Minister's authority is shot and she could be replaced by a new leader of the Conservative party who could shift the House of Commons behind one choice. Or not. There is also the growing possibility of another general election.
2020: As the deadline for Article 50 continues to slip into the future, there's no guarantee the UK will leave in 2019. This could see the UK still in the EU four years after the referendum decision to leave.
Never: There is one choice, unpopular with the majority of MPs, to never leave the EU. This could be achieved through a second referendum, a change in government, or MPs deciding Brexit is not worth the pain and potential damage to the economy.