LONDON, United Kingdom/BRUSSELS, Belgium - Britain will formally begin Brexit by triggering Article 50 of the EU's Lisbon Treaty on March 29, officials said on Monday, nine months after Britain voted to leave the European Union.
"We want the negotiations to start promptly," Prime Minister Theresa May's spokesman told reporters.
Britain's envoy to Brussels Tim Barrow "has this morning informed the office of European Council President Donald Tusk of the UK's intention to invoke Article 50 of the Lisbon Treaty on March 29," the Brexit ministry said in a statement.
Brexit minister David Davis was quoted as saying in the statement that Britons had approved a "historic decision" to leave the EU in the June 23 referendum.
"Next Wednesday, the government will deliver on that decision and formally start the process by triggering Article 50," he said.
"We are on the threshold of the most important negotiation for this country for a generation."
Britain voted by a 52 percent majority to leave the European Union -- the first member state ever to do so.
The divorce process under Article 50 gives a two-year framework for negotiations.
May has said she wants to leave the European single market in order to be able to control immigration.
The European Commission is expected to provide an initial answer to Britain's Article 50 notification within 48 hours but negotiations are not expected to start for several weeks or even months.
EU signals readiness for Brexit trigger
The European Union responded by saying it was fully prepared for Brexit negotiations, the European Commission said on Monday.
"Everything is ready on this side," Margaritis Schinas, the spokesman for European Commission chief Jean-Claude Juncker, told a briefing.
"Yes we have been informed in advance. We are ready to begin negotiations. We are waiting for the letter. Now we know it will come on the 29th."
EU President Donald Tusk tweeted that "within 48 hours of the UK triggering Article 50, I will present the draft #Brexit guidelines to the EU27 Member States."
However the actual start of talks between Britain and the EU is not likely for another six to eight weeks, EU sources told AFP.
Leaders of the remaining EU 27 states must first hold a summit to approve the guidelines. Officials say that is now likely to be held in early May.
Schinas said that the European Commission, the executive arm of the bloc, will then issue a formal recommendation to open Brexit negotiations shortly after the summit.
That will later be adopted by the 27 member states without Britain, which will give Commission Brexit negotiator Michel Barnier a mandate to actually begin talks.