Michael Brown: This leadership race is now wide open

There is no front-runner or favourite any more. Cameron, Davis and Ken Clarke - who jumped the gun last month - all have a more equal chance of winning, than we might once have thought. Mr Davis may have had the advantage during the phoney war, but this is no longer a shoe-in for him. The actual contest is now under way with a beauty parade at next week's conference in Blackpool and with Mr Cameron, having been stalled by Mr Clarke's launch during the summer, now back in business.

Mr Cameron stole the show yesterday with a glitzier launch (soft lighting, pastel shades and refreshments) than Mr Davis's more austere approach. Both had a master of ceremonies - Andrew Mitchell for Davis and George Osborne for Cameron - who introduced short speeches from their principal backers.

The only jarring note was struck at Mr Cameron's launch by Mr Osborne, who persistently referred to "Dave" in a ham-fisted attempt to portray his Old Etonian candidate as a man of the people. Be that as it may, Mr Cameron acquitted himself well with a polished performance, without notes, after a smooth video introduction. In terms of style he exceeded expectations. There was, however, just a slight hint of the Portillo launch of four years ago, which may turn off some of the crustier Tory MPs.

Mr Cameron's main pitch was to call for change in the Conservative Party, although I am not sure exactly what it is that he is going to change. He wants the party to reflect "modern Britain", and paid lip service to the need for more women candidates. What he did not say was whether this implied all-women shortlists - the only way Theresa May (who may herself enter the field) thinks that this will be achieved.

Mr Cameron is undoubtedly modelling himself on Tony Blair - down to the tie, shirt and suit - and paid tribute to the Government for introducing tuition fees, foundation hospitals and City Academies. Whether this respect for Blair - he made a back-handed attack on Michael Howard for calling Blair a liar - will impress Tory MPs remains to be seen. But, unlike Blair, he promised "no Clause Four moment". The generalities - "the Tories need to look and feel and talk and sound like a different party" ... we need to talk to people's hopes and not their fears" - tripped easily off his tongue. But I counted only a dozen MPs in attendance, who currently form the bulk of his support.

By contrast, Mr Davis spoke less well, although he appeared to be much heavier on specifics and has clearly used the summer recess to think about detailed policies. There was a much larger attendance of MPs, and a list of 55 MPs who have already pledged their public support accompanied his manifesto, Modern Conservatives - Changing Britain, Improving Lives.

Mr Davis used his humble origins to stress that Tory values and idealism are still needed, but should be directed to those at the bottom of the pile. He rejected suggestions that the Tories should "ape New Labour", and made it clear that lowering tax and spending wisely would be the bedrock upon which the poorest would be given a fairer deal. He wants a reduction in welfare dependency and a wider ownership of property, shares and pensions in order to extend power to poorer people. The solid manifesto of more detailed commitments that accompanied the speech enabled some of his supporters to claim that Cameron was all spin while Davis was all substance.

Mr Davis will probably be one of the two contenders to make it to the final run-off now to be decided by the 300,000 party members in November. Mr Cameron is probably, at this stage, fighting Mr Clarke - along with Liam Fox and Sir Malcolm Rifkind - rather than Mr Davis, for the other place in the final.

The tactical calculations of the various factions - notably the dozen-strong Cornerstone Group of Eurosceptic right-wingers led by Edward Leigh and Bill Cash - are leading to speculation that some MPs will give their first-ballot vote to Liam Fox as a way of knocking out either Mr Clarke or Mr Cameron. This is a dangerous game that was played in 2001 and resulted in Michael Portillo's elimination and the election of Iain Duncan Smith. Yesterday was Mr Cameron's day, although tomorrow is still more likely to belong to Mr Davis. But this is a much more open race than most of us initially imagined.

mrbrown@talktalk.net