The Sketch: Cable to Brown: you've gone from Stalin to Mr Bean

The scandals have knocked government business out of the news, and that worries them. But they're coming so often they're knocking other scandals out of the news and that worries us.

There's just no room for everything. This one isn't going to run is it? Judging from PMQs? But it's killed interest in the 25 million child benefit addresses. And that other one about the bank. Michael Spicer asked a brilliant question: where did the Bank of England find a spare 25bn to bail out Northern Rock? Yes, where? We heard no more of it. Oh, if only we didn't have the attention span of mayflies!

David Cameron failed to bring us hope this current excitement would last much longer. He certainly failed to better the Prime Minister. Mind you, the bar has risen over the past month. Success is now defined by the PM hurling his notes in the air with a gargling roar and launching himself across the despatch boxes to plunge his felt-tip pen into Cameron's jugular.

And it was possible. If the prime ministerial integrity could be compromised in public, on national television, then Gordon's talking compass (Sketch passim) might start yelling at him: "Are you going to let him talk to us like that! Burn him! Burn 'em all!" Many Tories would countenance a 1,500-point fall in the FTSE to see that.

But Cameron's first three questions went round a procedural wrangle about whether No 10 or the Electoral Commission should call in the police. Gordon can talk about this sort of thing indefinitely. Then there was something about the fellow called Mendelsohn but Gordon exonerated Mr M with a date. September 3, I think, so that was all right. All too soon it was time for the perorational abuse. Control freak. Complacency. Integrity. "Is he not cut out for the job?" A little vin ordinaire, I fear, just when we needed some premier cru.

No, Michael Howard should have written the questioning. We needed quiet, deadly clarity. Something that showed the precise way in which the Prime Minister's story unravelled over the past few days.

Vince Cable was superb. Again. He is a golden interlude in Lib Dem history. He is a holiday in Tuscany (not that you'd want to live there). When he said the PM had gone in a week from Stalin to Mr Bean there was opposition joy. Especially as Vince is no comedian. Mr Bean: Bumbling, accident-prone, selfish to the point of autistic it was crueller than it sounded at first. To be so mocked by a Liberal Democrat, that was a new low point.

But the PM is more vulnerable than we realise, because he can't do that talking thing we expect Prime Ministers to do. He pronounces words all funny. "Says" rhymes with "pays". "Bourne-mouth" (as in gob). The first syllable of "Kyoto" as in "cayote". It wouldn't matter but the sentences come out funny too, sometimes. Like John Prescott with a degree in history.

A small example. "I will do everything to protect the security of our armed forces". No, the armed forces are there to protect our security. Gordon's playbook says he will give the armed forces everything they need to protect OUR security.

Here's another one. "I will never refuse to act." He was replying to Michael Ancram's question on why nobody was telling him anything. "Why is everyone keeping him in the dark?" Answer: "I will never refuse to act." What? Never?

John Gummer recalled the PM's rubbish about death duties and why he'd called off the election, and asked, "So why should we believe his account of the dodgy donations?" Answer: "Because I do what is in the best interests of the country."

There is something brittle there in our famously doughty PM; Cameron hasn't quite found a reliable way to reveal it. But when he does the PM will be in difficulty. He lacks his predecessor's ability to mutate into something else.

simoncarr@sketch.sc