Who is David Cameron? What is he? After the ballots of Conservative MPs last week, the party has woken in the arms of the young David and now pauses to ask how it got there and what it knows of the character of the man.

Cameron’s campaign has been a masterpiece of vagueness. “Let’s dream a new generation of Conservative dreams,” he told the party conference. It was with such vacuous rhetoric that he won a standing ovation. The Pied Piperof Hamelin was scarcely more hypnotic. Hard-bitten media hacks, creatures who have devoted their lives to being cynical, were drawn into his trance.

In his film Being There, Peter Sellers played a simpleton, Chance, a gardener. He smiles sweetly and speaks softly. His only conversation is about seeds, plants, seasons and the like. By a series of accidents he is mistaken for a wise man who has chosen to speak only in metaphors. When he says that we reap in the autumn what we plant in the spring, sages nod their heads admiringly. Before long he has become a national hero, a familiar figure on television chat shows, a man whose counsel is sought by the president.

Cameron is far from being a simpleton. The fact that he has within the space of three weeks become a household name on the back of spouting platitudes is not a criticism but an accolade. Some people have a manner that predisposes people to think well of them. Cameron has it, as Tony Blair did once.

When Blair said that he wanted to be “tough on crime and tough on the causes of crime”, hangers and floggers latched on to the first half of the sentence and social liberals to the second. It was as though each group could hear only the thought with which it agreed. Cameron has a similar magic.

Journalists have begun to wake from their reverie and now recall that they are programmed to be professionally sceptical. They demand to know what Cameron’s policies are.

On his campaign website I clicked on the icon “policy programme” and for a few delicious moments a blank page appeared with the words “unknown zone” (before eventually revealing a newspaper article by him, purportedly on policy but actually composed of brilliant generalisations).

I hope that he will stick to imprecision. If during the coming six-week election campaign among Tory members he gives in to pressure to announce policies, it could cripple his leadership before it has started. His predecessors William Hague, Iain Duncan Smith and Michael Howard sought to define themselves by their policies and perished. Their new ideas were variously mean-spirited, illiberal, silly, opportunistic and inconsistent.

You might think that Cameron the Tory moderniser is in no such danger. But he is. He talks of lower taxes and stable families and is sceptical on Europe. In those three cases, were he to move his position even an inch to the right he would take the Tories back to the attitudes on which they lost the last two elections.

He must cling to vagueness as steadfastly as he stood by his refusal to answer questions about what drugs he might have taken. For the three years between becoming party leader and then prime minister, Blair fed us nothing but pleasing soundbites. Cameron should do the same.

In another part of his website Cameron tells us that he is no “Tory Blair”. It is fine to say that, as long as he does not really think it. “Tory Blair” is exactly what he is. That is the whole point of him. For the first time in ages the Conservatives have found a (potential) leader who attracts rather than repels.

While in opposition Blair got away with little policy content because he was then frenetically reforming his party. That satisfied the media’s appetite. Cameron must fill the vacuum by doing the same. Blair was able to shed his early “Bambi” image by his ruthless imposition of change on his party. Cameron should follow suit.

Blair had a project to make the party electable. It mattered to him more than everything else in the world put together. Policies, traditions, ideas, vested interests and people who did not conform with the project were mercilessly tossed into the shredder. So, too, if tax cuts, stable families and Euroscepticism do not fit the new Conservative project, whatever sentimental attachment Cameron may have to them, they also must be torn up.

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