BREXIT - Theresa May signs historic letter to trigger Brexit and begin irreversible process to leave European Union(EU) Tuesday March 28,2017

Theresa May will urge Britons to come together when she triggers Article 50 today

In a statement to MPs, the Prime Minister will say now is the time for national unity to achieve the best possible Brexit deal.

She will say we should be ‘no longer defined by the vote we cast, but by our determination to make a success of the result’. ‘We are one great union of people and nations with a proud history and a bright future,’ she will add.

‘Now that the decision has been made to leave the EU, it is time to come together.’

Sat in the cabinet office of Downing Street, May last night signed her name under the watchful eye of Sir Robert Walpole, the country's first ever Prime Minister

Theresa May officially invokes Article 50 as she signs a letter to EU Council President Donald Tusk, under the watchful eye of Britain's first Prime Minister Robert Walpole

The letter will be handed over by Britain's EU ambassador Sir Tim Barrow and represents the first act of an irreversible Brexit process