The Tory leadership race has taken a surprising turn. Until recently it looked like being a run-off between David Davis, the shadow home secretary, and David Cameron, the education spokesman. Mr Davis would represent the voice of Conservative experience, Mr Cameron would carry the torch of the modernisers. But then, a fortnight ago, that old bruiser Ken Clarke threw his battered fedora into the ring and transformed the contest. The former chancellor, 65, far from representing the Tories’ One Nation past, is seen by a surprising number as its future.

While Messrs Davis and Cameron have been dithering about the timing of their declarations to enter the contest, Mr Clarke has stolen a march on them, as Margaret Thatcher did in 1975 by choosing to go early against Edward Heath. Our YouGov poll today shows that he is easily the most popular of the candidates among voters in general. Of those who declared a view he polled 42% support, compared with 16% for Mr Davis, 9% for Liam Fox, who announced his candidature last week, and just 6% for Mr Cameron and Sir Malcolm Rifkind. Even among Tory voters, for whom Mr Clarke’s pro-European views are about as welcome as a night out with Peter Mandelson, he was comfortably ahead. Another YouGov poll yesterday, of Tory party members only, also showed Mr Clarke in the lead. There are many twists and turns to come, and the contest could yet be delayed until next year, but the former chancellor is making the running.

The Tory problem will not end with a new leader. Today’s poll also shows that while Labour is five points ahead of the Tories, that gap would double if Gordon Brown became Labour leader and Mr Clarke led the Tories. Under Mr Davis the gap would be even wider. Replacing Tony Blair with Mr Brown will do more for Labour, particularly in winning support back from the Liberal Democrats, than any change of leader can do for the Tories. The issue for Conservative MPs is whether they have a potential leader who can dent Mr Brown. The risk is that they don’t.