Boris Johnson backs Theresa May's Brexit credentials

Boris Johnson has burst on to the General Election campaign stage declaring that Theresa May will "pull it off" in Brexit negotiations.After claims that some Cabinet ministers want the Prime Minister to sideline him, the Foreign Secretary has made a powerful speech praising her leadership.In his first major intervention in the campaign, at the Lord Mayor's Banquet in the City of London, Mr Johnson strongly endorsed Mrs May's Brexit strategy.