The Sketch: The end of the world is here - keep calm and carry on

The Prime Minister found himself in what passes for existential danger at PMQs. If he lost his temper he'd lose everything. What with his personal poll collapse, the Government's loss of authority, credibility and dignity – the national necessity was that for half an hour Cameron didn't go red and get shouty.

Just to give this, as they say round here, a little context. The euro is entering its end game, Greece is on the brink of a social apocalypse, the world's monetary system could disappear down a black hole leading to global systemic collapse.

But the Labour task in the Commons was to make the PM go red and shout so they could laugh at him. At one point, the Leader of the Opposition asked, "Wha' is 'e on?" He did. Exactly like that. About President Hollande's attitude to public spending. The glottal stops were particularly masterful.

The noise level was building – at the Labour line "a recession made in Downing Street", the Tory bench monkeys rose as one monkey going "Hoo! Hoo! Hoo!" But Ed Balls could see the PM was calmed by the support so he used his big bazooka. With one large, slow hand he waved in the PM's face, "Calm down, dear!"

And Cameron didn't vault the dispatch box screaming: "I'll smash your stupid face in!" He took a breath and said, with extreme calm: "I am extremely calm." But then Balls launched a brilliant variation – the double-handed "Calm down dear". It is three times as annoying. It's just as well he's not an octopus.

Cameron's general response was unexpected and effective. He exerted himself to give extra courteous replies to Peter Hain, Simon Danczuk and Alan Johnson. He even laughingly told Meg Hillier to look elsewhere for a "smoking gun" in the Murdoch affair. (Aha! So there is a smoking gun?)

In the end, we were half an hour closer to the end of the world, but very little wiser.