I'm late with this, but for those who like the Boris Johnson approach to politics, here is his column from last week on the Clegg Effect. Best quote is this, concerning his view of Clegg's performance in the debate:
He [Clegg] was by far the worst, with many of his answers seeming to be semi-masticated versions of something Cameron had already said. And so you can imagine my amazement when those polls started to come in, and the news that the punters overwhelmingly scored it for Cleggie. It was one of those times when there seems to be only one solution to the problems of British politics, and that is to dissolve the electorate and summon a new one.