(Credit: AP Photo/Evan Vucci) Let the Brexit begin. Nine months after an historic vote, in which more than 50 percent of the British population voted to leave the European Union, the movement has officially begun. U.K. Prime Minister Theresa May has signed an official letter Wednesday, starting the official movement to withdraw the United Kingdom from the European Union. “This is a historic moment from which there can be no turning back,” the prime minister told Parliament. The letter, signed in Brussels, made the U.K.