Cameron in last ditch appeal to Boris Johnson; Don't join Brexit campaign

David Cameron has issued a last-ditch appeal to Boris Johnson not to join the campaign for Britain to leave the European Union.

With the London mayor set to end months of speculation over which side he will back, Mr Cameron said it would be a "wrong step" for Mr Johnson to link up with Ukip leader Nigel Farage and Respect's George Galloway in the "out" camp.