I AGREE with most of the conventional wisdom about last night's debate.

I actually rather liked Gordon Brown's joke about the poster and Lord Ashcroft. But he was a little too belligerent, and was trapped by the basic tension between promising change and defending his record. At the very beginning I thought David Cameron was going to walk it: he trumped the other two in his opening remarks by apologising for the expenses scandal and maturely conceding that Labour had got some things right. But then he waffled on immigration and, in general, went in for too many personal anecdotes (though he was strong on the national insurance row).

Nick Clegg grasped the need to talk through the camera to the audience at home better than the other two. And whereas Vince Cable's central position in the chancellors' debate helped to make him look statesmanlike, Mr Clegg's position at the side of the stage supported his bid to portray himself as an insurgent. He has always been more persuasive and personable than the lack of coverage he generally commands would suggest. It isn't surprising that voters seem to have warmed to him—though I half-expected his liberal stance on prisons and views on Trident to put people off.

The question is, what difference will it (and the other two debates) make to the election result? A boost in the Lib Dem vote helps them, obviously, in the Lib-Tory marginals. But it would also have other, less predictable consequences elsewhere. And it is not yet clear whether liking Mr Clegg's television manner will translate directly into votes.