29 March to be article 50 trigger day

Formal notice of the United Kingdom's intention to leave the European Union will be given oin Wednesday 29 March, the Prime Minister's office said today.

The notice, under article 50 of the Lisbon Treaty, signals the start of the negotiation process to settle the terms of the UK's departure, which takes effect two years from the giving of notice unless an extension is agreed. 

Mrs May hopes that negotiations will begin as quickly as possible. On being informed of the date by the UK's ambassador to the EU, European Council President Donald Tusk said in Twitter that he would present the draft Brexit guidelines to the 27 remaining member states within 48 hours of the notice.

A UK Government spokesperson said ministers "fully appreciate it is right that the other 27 EU states have time to agree their position".

The EU hopes the talks will be concluded by October 2018, to allow the outcome to be approved by the UK and European Parliaments, as well as by the necessary majority of EU states.