LONDON, ENGLAND - JULY 12: Prime Minister-in-waiting, Theresa May, reacts to photographers after walking to the wrong car after attending a Cabinet meeting at Downing Street on July 12, 2016 in London, England. David Cameron will step aside tomorrow (Wednesday) after his final Prime Minister's Questions allowing current Home Secretary Theresa May to move into 10 Downing Street. She was selected unopposed by Conservative MPs to be their new leader. (Photo by Carl Court/Getty Images)

LONDON, ENGLAND - JULY 12: Prime Minister-in-waiting, Theresa May, reacts to photographers after walking to the wrong car after attending a Cabinet meeting at Downing Street on July 12, 2016 in London, England. David Cameron will step aside tomorrow (Wednesday) after his final Prime Minister's Questions allowing current Home Secretary Theresa May to move into 10 Downing Street.  She was selected unopposed by Conservative MPs to be their new leader.  (Photo by Carl Court/Getty Images)