The United Kingdom will formally start the process of leaving the European Union on 29 March, the government said today.
Sir Tim Barrow, Britain's permanent representative to the EU, has told European Council president Donald Tusk the UK intends to invoke Article 50 on that date, it was confirmed in a statement today.
Triggering Article 50 is required to start the process of leaving the EU, although the negotiations could stretch out over years. According to the official timetable, the UK should exit the EU in March 2019.
In a statement, Brexit minister David Davis said: "We are on the threshold of the most important negotiation for this country for a generation.
"The government is clear in its aims: a deal that works for every nation and region of the UK and indeed for all of Europe – a new, positive partnership between the UK and our friends and allies in the European Union."
A European Union spokesperson confirmed to the BBC they were “ready and waiting” for the formal letter.
Once prime minister Theresa May officially invokes Article 50 next week, she is expected to make a statement to the House of Commons.
Downing Street expects that in the immediate aftermath of triggering Article 50, the remaining 27 EU member states will agree terms and give an initial response within 48 hours.
A government spokesperson, while stressing they wished to exit the EU as quickly as possible, said they "fully appreciate it is right that the other 27 EU states have time to agree their position”.
Scottish MPs claimed to have not been informed by Westminster, with Michael Russell, Scotland’s Brexit minister and MSP for Argyll and Bute, tweeting angrily in the immediate aftermath.
Alyn Smith, MEP representing Scotland in the European parliament, also criticised the British government's "arrogance only matched by ineptitude", in the wake of Ireland, Wales, and Scotland's parliaments all failing to be informed ahead of the announcement.
It comes nine months after a UK referendum found 51.9% of people who voted wished to leave the EU, versus 48.1% who wanted to remain.
The announcement kiboshes earlier suggestions of a snap election, which speculation this morning had put on 4 May, with a spokesperson pushing strongly back against the possibility of any vote before 2020.
This is a developing story. Follow @BuzzFeedNews for updates.
Rose Troup Buchanan is a reporter for BuzzFeed News and is based in London.
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