The prime minister's spokesman has confirmed that Theresa May will trigger article 50 on Wednesday, March 29, initiating the formal process for the UK to leave the EU.
As per May's Ocotber speech on the subject, the letter formally submitting parliament's intention to start the Brexit process was expected to reach the EU by the end of March.
Downing Street confirmed today that the letter will be formally put to the EU's 27 other member states on March 29, with the hope of beginning negotiations "as quickly as possible".
The formal process is expected to take two years according to an official table setting out deadlines, which - if stuck to - would see the UK officially become autonomous in 2019.
What happens now?
Negotiations will begin to outline a UK Brexit deal, which could include trade deals - although this might be handled separately.
Article 50 is part of the Lisbon Treaty which was created in 2009 to provide a formal plan for any country which wishes to leave the EU.
It states that any exit deal must be approved by a "qualified majority" (72% of the remaining 27 EU states) and must also get the backing of MEPs.
Later this year, the UK government is expected to introduce legislation to leave the EU and put all existing EU laws into British law, known as the Great Repeal bill.