大象传媒

Britain has formally notified the European Union of its intention to leave, initiating a period of negotiations. UK Prime Minister Theresa May said it marked a "historic moment" and a "unique opportunity". The triggering of Article 50 gives both sides two years to reach agreement unless both sides agree to extend the deadline for talks.

(Photo: Britain's ambassador to the EU Tim Barrow delivers British Prime Minister Theresa May's formal notice of the UK's intention to leave the bloc under Article 50 of the EU's Lisbon Treaty to European Council President Donald Tusk in Brussels. Credit: Emmanuel Dunand/AFP/Getty Images)