BOris Johnson pledged to remove Britain from the EU by 31 October when he launched his prime ministerial campaign.

The former Foreign Minister said it was time to "remember our duty to the people and the reasons for the Brexit vote."

He pledged to create the "clarity" of the vision needed to reach the outcome of the EU referendum, with or without agreement, and warned MPs that they would face "mortal retaliation" by voters if they failed would try to stop the Brexit.

Mr. Johnson relied heavily on his papers in eight years as mayor of London to prove that he could beat Labor at the ballot box, and insisted on questions about his integrity: "I do what I promise …