The Sketch: Trap set, Cameron watched as Brown bit

Lib-Dem innovation. They break the mould, don't they? The new leader sat halfway down the front bench – "in the middle of his team," as one put it.

He looked good, and that's important for a leader. He looked nice, too. The smile was particularly engaging. What was his line of questioning? Ah, now you ask too much. I do remember him saying 25,000 people would die this winter as a result of government policy. That's more than Iraq, so I wish I'd paid more attention. But what a nice smile, so at least we'll die happy.

Cameron danced about the PM, jabbing him. He can even improvise, much harder than it looks in the Theatre of Cruelty. The PM can't do it at all. He scoffed at Cameron for using "lines prepared in front of the mirror". That brought the Tories off their seats: "You! That's what YOU do!"

Is the PM in favour of compulsory ID cards? It's a brilliant question because he won't answer it. He said it was up to Parliament, even tried a new tack with, "All the evidence of the past few months..." but got stuck for a suitable conclusion. The pause was filled with a great roar of Tory scorn.

The tactic was to present the PM as incapable of a straight answer. And he plays into it so well.

One of Brown's funnier flaws is that everything he says must have multiple meanings. It's why he can't do spontaneity, and why he sounds mangled and untrustworthy.

When Cameron went on to capital gains tax (up or not?) Brown produced his (rehearsed-in-front-of-a-mirror) counter: did Cameron favour compulsory ID cards for foreigners? "If he can't answer that he's not fit to ask other questions!" the PM concluded in a way that made him sound unfit for office.

Gordon faces humiliation on this. The argument he's relying on doesn't hang together; a well-aimed blow will bring it all down around him. Odd, for such a great brain, isn't it?

simoncarr@sketch.sc