The UK government will start divorce talks with the EU when Article 50 is invoked on Wednesday 29 March, Downing Street confirmed on Monday (20 March).
The Treaty base for splitting from the economic and political bloc is the 2009 Lisbon Treaty, otherwise known as the Reform Treaty.
British Prime Minister Theresa May will now have to write to newly re-elected European Council President Donald Tusk to invoke Article 50 of the Lisbon Treaty, with Brexit Secretary David Davis or Sir Tim Barrow, the UK's representative to the EU, delivering the letter.
Tusk will then consult the other 27 leaders of the Council on the Brexit trigger. A response from the group is expected in around 48 hours after the UK's notification, according to European Commission negotiator Michel Barnier.
The EU leaders will later hold a summit in April or May to decide a final response. The top politicians will carve out negotiating positions and guidelines for the European Commission, the bloc's executive arm, to follow.
Jean Claude Juncker, as European Commission president, will oversee the process, while Barnier and his taskforce of negotiators deal with the UK government for the next two years. The Belgian capital of Brussels is expected to play host to most of the talks between EU and UK officials.
Barnier has said that he expects a deal to be agreed in 2018 and ratified in 2019.
If the UK fails to secure an agreement with the EU, it will be forced to trade with the bloc on default World Trade Organisation (WTO) rules. The Belgian capital of Brussels is expected to play host to most of the talks between EU and UK officials.
May, meanwhile, has promised to invoke Article 50 by the end of March. The UK prime minister outlined her 12-point Brexit plan during her Lancaster House speech in London.