MANCHESTER, ENGLAND - APRIL 15: (EDITOR'S NOTE: Alternative crop of image #521392588) London Mayor Boris Johnson addresses supporters during a rally for the 'Vote Leave' campaign on April 15, 2016 in Manchester, England. Boris Johnson is taking part in a 48 hour 'Brexit Blitz' of campaigning in Northern England. Britain will vote either to leave or remain in the EU in a referendum on June 23.  (Photo by Christopher Furlong/Getty Images)