Boris Johnson to campaign for Brexit in EU referendum

London mayor defies David Cameron’s plea to support EU membership, saying he will advocate UK’s withdrawal after ‘huge heartache’ over decisionBoris Johnson has transformed the terms of the EU referendum debate by announcing that “after a huge amount of heartache” he is to throw his weight behind the campaign to take Britain out of the EU. The London mayor announced on Sunday that he will campaign for a leave vote after concluding that David Cameron’s de