Britain's new Prime Minister Theresa May speaks outside 10 Downing Street in central London on July 13, 2016 on the day she takes office following the formal resignation of David Cameron. - Theresa May took office as Britain's second female prime minister on July 13 charged with guiding the UK out of the European Union after a deeply devisive referendum campaign ended with Britain voting to leave and David Cameron resigning. (Photo by JUSTIN TALLIS / AFP)        (Photo credit should read JUSTIN TALLIS/AFP/Getty Images)