UK leader Theresa May addresses Parliament as official Brexit negotiations begin

Article 50 letter delivered, there is no turning back: UK PM May

U.K. Prime Minister Theresa May took questions from Parliament Wednesday and addressed the House regarding the triggering of Article 50, the clause in the Lisbon Treaty which began the formal process of the U.K. exiting the European Union.

CNBC has all you need to know about Article 50 and the Brexit process as well as a round up of how the U.K. media is covering the historic event.

I want the UK to be a best friend to our European partners: UK PM May

A handwritten letter notifying the EU of the U.K.'s intention to leave was delivered to Donald Tusk, the president of the European Council, by Tim Barrow, the U.K.'s ambassador to the EU, at 12:20 p.m. London time.

Immigration system will serve national interests: UK PM May