EU leaders have given the green light for the second stage of the Brexit negotiations to begin, what happens next?
December 19 - The Cabinet will discuss what sort of long-term relationship they want Britain to have with the EU after it has withdrawn from the bloc.
December 20 - Ministers face the prospect of a second Commons rebellion on the EU (Withdrawal) Bill over plans to write the Brexit date into law.
2018Winter/spring - Negotiations on the transition to future EU/UK relations, along with "exploratory talks" on a possible free trade agreement.
March 22-23 - European Council summit in Brussels. An opportunity to assess what kind of trade deal can be expected.
May - English local government elections will provide the Prime Minister Theresa May with her first widespread electoral test since the disastrous snap election of June 8 2017.
October - A final treaty on withdrawal and transition should be ready by this point in order to allow time for ratification before the end of the two-year Article 50 deadline. EU chief negotiator Michel Barnier says that it is only at this stage that the "real negotiation" on a free trade deal will begin, and that the parties will be "hard pressed for time" to conclude this before the March 2019 date of Brexit.
Winter/spring - Ratification process involving as many as 38 national and regional parliaments, with any of them effectively holding a veto.
Brexit Secretary David Davis has promised that Parliament will have to approve any deal in a Withdrawal Agreement and Implementation Bill, although this will be on a "take it or leave it" basis. MPs will consider the legislation before MEPs in the European Parliament carry out the final vote on any agreement.
March 29 - Two years after the invocation of Article 50, the UK ceases to be a member of the EU and is no longer subject to its treaties, whether or not a withdrawal agreement has been reached. Because the exact moment of exit is midnight Brussels time, the UK is due to leave at 11pm on March 29. Under the terms of the EU (Withdrawal) Bill, the bulk of Brussels legislation would be automatically transposed on to the UK statute book.
June - European Parliament elections will take place without the UK.
2020December 31 - Britain ceases payments into the EU budget.2021If a two-year "implementation period" is agreed, Britain will finally move to its new relationship with the EU in the spring of 2021, ceasing to observe EU rules and regulations.2027Expected end of the European Court of Justice's role in the oversight of the rights of EU citizens living in the UK.