LONDON, UNITED KINGDOM - MARCH 28: : (----EDITORIAL USE ONLY MANDATORY CREDIT - PRIME MINISTRY OF THE UNITED KINGDOM / HANDOUT " - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS----) British Prime Minister Theresa May signs the official letter to European Council President Donald Tusk invoking Article 50 and the United Kingdom's intention to leave the EU on March 28, 2017 in London, England. After holding a referendum in June 2016 the United Kingdom voted to leave the European Union. (Photo by PRIME MINISTRY OF THE UNITED KINGDOM / HANDOUT /Anadolu Agency/Getty Images)