Cameron camp hit by sleaze claims against top ally

The News of the World reported that the 34-year-old, married father of two admitted he knew her, and acknowledged one of his best friends fathered her child and became a drug addict. Mr Osborne's close friend Mr Cameron, the shadow Education Secretary, is himself embroiled in a controversy over his refusal to state whether he used drugs before he entered politics. On Friday, Mr Cameron acknowledged that a close family member went through a "dreadful problem" with narcotics, adding that he was "incredibly proud" of the way his relative had come through their difficulties.

Last night, Mr Osborne suggested that he was the victim of a "smear campaign". In a statement, the MP for Tatton said: "The allegations are completely untrue, and dredging up a photo from when I was 22 is pretty desperate stuff."

Mr Cameron's supporters, meanwhile, accused his main rival of hypocrisy after David Davis said politicians should "give straight answers to straight questions". They said a year ago Mr Davis refused to say whether he had smoked cannabis, and added the shadow Home Secretary prepared a briefing note for colleagues detailing how Tony Blair and his Cabinet stonewalled drugs questions.

Nicholas Soames, a leading Cameron supporter, said: "Davis has got plenty of form for this sort of thing. When he said people should 'speak no ill of a fellow Conservative' you could hear the sound of people throwing up into buckets at the sheer hypocrisy of the man."

The frontrunner's momentum will be further checked by the results of an exclusive poll for The Independent on Sunday which shows Mr Cameron would fare no better than his rivals in a contest with Gordon Brown. Leading campaigners, including former government drugs tsar Keith Hellawell, have called on Mr Cameron to "come clean" on the drugs issue.