So, who won? Well, it depends what you mean by "won". Nick Clegg certainly gained most from the evening. He was confident, coherent and had a strong line on almost every policy area, whether you agreed with those lines or not. And he gained by positioning himself against what he calls the "old parties", and by painting his own party as the opponents of the status quo. Indeed, early polling seems to be bearing this out, and the bookies have even cut the odds on Clegg being the next home secretary.
But Cameron won in a different sense, in that he far outperformed Gordon Brown. In other words: I can't see Labour closing the gap on the Tories because of tonight's debate, and, if anything, the gap might increase. The difference between the two men was chiefly one of personality. Cameron humanised many of the issues, whereas Brown tried to use them as clubs against his Tory oppone. Cameron brought energy to the stage. Brown brought scowls, frowns and jibes about Lord Ashcroft.
To be fair to the PM, he picked up as the debate proceeded – at least by his standards. And he can derive a grim hope from the fact that the next two debates might be slightly more geared towards his technocratic drone. But, really, tonight doesn't augur well for him. He needed a victory. He finished last.
UPDATE: ITV's poll results have come in, and it's a big victory for Nick Clegg. 43 percent of respondents thought he did best. Cameron scored 26 percent, and Brown 20 percent.