DAVID CAMERON, the young moderniser who has promised the Tory party a dream of a brave new future, will first have to contend with unsettling questions about his past.

It seemed an effortless journey from Eton to Oxford, where he gained a first in philosophy, politics and economics, to the Tory research department and then the Treasury during the biggest crisis since sterling’s devaluation in 1967. But now “Dave”, as his friends call him, faces intense scrutiny over his political beliefs and pointed refusal to discuss whether he has taken drugs.

Mr Cameron had been catapulted in seven days from backroom boy to the front of the leadership queue after a bravura twenty-minute conference speech and slick launch of his campaign, which had flatlined through the summer. But the man who came from nowhere has discovered that his past is being raked over by 197 MPs sifting for clues about where he might take them, because his campaign had been deliberately vague on detail. His enemies have been searching for a potential fatal weakness — which they think they might have identified in drugs.

Yet Mr Cameron had feared that the biggest problem about his past would be his Old Etonian background. He is a descendant of Henry VII through the monarch’s daughter, Mary Tudor, and her marriage to the Duke of Suffolk.

But a routine question at the party conference over whether he had taken cannabis has turned into an increasingly media-driven campaign about whether he took hard drugs. The Daily Mail yesterday ran a full-page editorial demanding the answer.

Mr Cameron will not have been surprised by the intervention. He has privately pledged to sacrifice some of the party’s core voters, who loathe the modernisers’ talk of inclusivity and social liberalism, in an attempt to reach out to a new generation of younger voters. He would do so by deliberately alienating the Daily Mail and its sister paper, The Mail on Sunday, whose vitriolic tone he abhors.

However, writing in the Daily Mail today, Mr Cameron again refused to say whether he has taken drugs. In a carefully worded article designed to pacify his critics, Mr Cameron insisted he was not soft on drugs. He said: “Britain needs a government prepared to take the tough but thoughtful action necessary to fight back against the scourge of drug abuse in this country.” One leading supporter, an MP who accepts he could lose his seat because of the strategy, said: “We may, for a while, lose up to 7 per cent of our vote, taking us down to 25 per cent. But it is worth it if we can fundamentally change the party.” Associated Newspapers knows about the Cameron doctrine so it is no coincidence that it has sent its reporters to delve into his past and that of his friends.

A friend of Mr Cameron said: “It is his first big test of leadership. Dave cannot give in to the Mail now or when he is leader.” On Question Time on BBC One on Thursday Mr Cameron fluently defended his decision to have a private life “before politics” and was buoyed, according to his supporters, by the support of the audience and the Labour minister Ben Bradshaw.

While Mr Cameron is silent about his personal experience, on drugs policy he is radically different from most Tories. He is the only leadership candidate not to have supported calls for the law on cannabis to be tightened again. In 2002, he declared that heroin addicts should be given diamorphine to stabilise them to wean them off the drug. He said: “One of the things that has held back the debate is the politicians’ attempt to appeal to the lowest common denominator by posturing with tough policies and calling for crackdown after crackdown.”

Tory MPs will be asking this weekend if the fresh-faced Old Etonian is big enough to withstand the pressure. His friends in the media highlight his pivotal role on Black Wednesday, when he was a special adviser to the Chancellor, to show that he has proved his mettle. Alice Thomson, a close friend and holiday companion, wrote in her Daily Telegraph column: “He did not crack when advising Norman Lamont during the exchange-rate mechanism [ERM] debacle.” But one key player at the time said: “I keep reading David was so calm in the crisis. But he was never in the firing line. What strain was he under? He was a spectator. He was not in any of the key meetings. He had nothing to do with it.”

Just before the pound crashed out of the ERM, Mr Cameron gave Mr Lamont a cigar with a note which said: “By the time you’ve smoked this, all your troubles will be over.” Mr Lamont has never smoked it.

Mr Lamont was impressed by Mr Cameron. “He was a first-rate political adviser,” he said. “I cannot believe anyone had one better. He was sharp and had original ideas. I saw in him someone who would play an important role in the Conservative Party.” Mr Cameron’s family is steeped in Tory tradition. His great and great-great-grandfathers were Tory MPs for Newbury. His father, Ian, was a stockbroker, his mother, Mary, a magistrate in Berkshire. He has an older brother and younger sister.

After Oxford he fell in love with Samantha Sheffield, who was an art student at Bristol University and the best friend of his sister, Clare. Samantha, 34, is the daughter of Sir Reginald Sheffield, a baronet who has a 300-acre estate in Lincolnshire. Her mother Annabel is now married to Viscount Astor. Samantha sports a green tattoo above her instep, which would surely be a first for a Tory First Lady. The romance blossomed at weekends in Bristol, which had spawned a set of multi-ethnic bands playing a new type of music called trip-hop. This was when Samantha met Tricky, a talented council-estate boy who smoked “skunk” marijuana and rapped on dance tracks. In 1994 he said that he smoked in order to be able to create music.

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