30/09/2013 15:36 BST | Updated 30/09/2013 15:41 BST

Boris Johnson Tells Nigel Farage's Wife Not To Vote Ukip

The Mayor of London Boris Johnson speaks to delegates during the Conservative Conference 2013, held at Manchester Central

Boris Johnson has revealed he was invited to speak at the Ukip party conference in London - by Nigel Farage's wife.

Addressing a rally for activists at the Conservative Party conference in Manchester on Monday evening, the mayor of London said he had received a "really heartwarming letter" from Kirsten Farage who he suspected was the "brains" and the "power behind the throne", but had decided to decline the offer.

"I was very flattered and amused. My instinctive reaction was to say yes. But then I thought, no. No, no, no. This is the moment to lash my self to mast and resist the siren song of Kirsten," he said.

"With a general election less than two years away, there is only one relevant fact, there is a risk the party she supports would deprive [people] of the chance to have a vote in a EU referendum because they would help put Miliband back in power."

Boris was speaking one the same day that Farge [Nigel] had been attempting to draw attention away from the main conference centre by taking part in three fringe events outside the secure zone. Including one which clashed with the timing of Boris' rally.

"My message to the charming Mrs Farage," he said. "Is don't vote for Ukip, don't even think about it, because we will see this country sleepwalk into a Labour government".

Boris, who was stressing his loyalty to David Cameron and he had no plans to lead the Tories "ever, now, whenever", also could not resist one joke at the prime minister's expense.

"Ukip if you want to," he said. "David Cameron's not for kipping. Unless obviously he is at his sister-in-law's wedding."

The mayor's profile at this year's conference is much lower than it was last year, when he was mobbed by journalists as he arrived in Birmingham as speculation over his plans to run for Tory leader was at its height.

Boris may remain as popular with the party grassroots now as he was in 2012, but he made his entrance with much less fanfare. The mayor may have heeded Ken Clarke's advice to "cool it" if he wanted to succeed Cameron.