Johnson: You'd be nuts to join Ukip

London mayor Boris Johnson has issued an appeal to would-be Tory defectors urging them not to break ranks and join Ukip.

Writing in his weekly column in The Daily Telegraph, he said Conservative MPs would be “utterly nuts” to desert the party for Ukip as they simply risked handing power to Labour at next general election.

Mr Johnson said he believed reports that two or three more MPs were preparing to follow defector Mark Reckless and jump ship were “fanciful”.

He nevertheless appealed directly to any who were considering the move not to do so.

“Let me try to reason with any in my party, the folk who want to launch themselves headlong into the silage, because I genuinely think that they (if they indeed exist) must be utterly nuts,” he wrote.

“There are only two people who are in a position to take the keys to Downing Street next May, and they are David Cameron or Ed Miliband. I know that you disagree vehemently with most of what Ed Miliband says and does – and so I must urge you not to allow the disaster of a Miliband premiership.

“If you really want to let this country sleepwalk into a Labour government, then that is your prerogative. You can close your eyes and let it happen. You kip if you want to; the rest of us are going to fight and win.”