David Cameron has come to the defence of Grant Shapps after the Conservative chairman was accused of anonymously editing his own entry, and those of other Tory politicians on internet encyclopaedia Wikipedia.

The Prime Minister was asked about Mr Shapps and insisted the Welwyn Hatfield MP was doing a "great job".

"He's made a very clear statement about this and I've got nothing to add to that," said Cameron.

Earlier, Liberal Democrat leader Nick Clegg mocked Shapps, who used the pseudonym Michael Green for his internet business.

"Well, Grant Shapps has firmly denied he had anything to do with it; he himself does not have the time to edit his own Wikipedia entry, and look I'm prepared to believe him. It just could have been someone else: Michael Green, for instance," said Clegg.

The Liberal Democrat MP for Yeovil, David Laws added that he thought the Conservative party and Grant Shapps needed to be "open" about what happened."

"Well I think there are some allegations to answer here about something which it sounds quite extraordinary. But this really looks more like a dog fight within the Conservative party, if it's true that some Conservative has been writing things about other Conservatives," he said.

Shapps told the BBC the allegations, originally reported by the Guardian were "categorically false and defamatory".

"It is the most bonkers story I've seen in this election campaign so far," he said.