LONDON, ENGLAND -  JUNE 21:  Boris Johnson, Gisela Stuart and Andrea Leadsom arrive for the EU debate at Wembley Arena on June 21, 2016 in London, England.  Tonight the BBC is hosting a live, two-hour televised EU debate in front of an audience of 6,000 at Wembley Arena, which sees the Leave campaign represented by Conservative MP Boris Johnson, Labour MP Gisela Stuart and Conservative MP Andrea Leadsom, and the Remain campaign represented by London Mayor Sadiq Khan, Leader of the Scottish Conservative and Unionist Party Ruth Davidson, and Frances O'Grady, General Secretary of the British Trades Union Congress. (Photo by Stefan Rousseau-WPA Pool/Getty Images)