London (dpa) - Prime Minister Theresa May late Tuesday signed the letter which will trigger Britain‘s exit from the European Union, according to a photograph seen by dpa.The letter, which invokes Article 50 of the Lisbon Treaty, is to be hand-delivered to European Council President Donald Tusk in Brussels by British Ambassador to the EU Tim Barrow at 1130GMT.After chairing a Cabinet meeting in the morning, May will then address Parliament at around the same time the letter is delivered, when she will tell lawmakers that she wants to represent "every person in the UK," including EU nationals, in Brexit negotiations."It is my fierce determination to get the right deal for every single person in this country," she will say."For, as we face the opportunities ahead of us on this momentous journey, our shared values, interests and ambitions can, and must, bring us together."Britain voted to leave the EU in June, after campaigns which divided the country. Scotland and Northern Ireland voted overwhelmingly to remain in the EU, while England and Wales, with a much larger combined population, voted to leave.May spoke to Tusk and European Commission President Jean-Claude Juncker by phone late Tuesday, with Juncker saying his conversation had been "good and instructive."