The Sketch: Irritating Eds finally succeed in upsetting Cameron's composure

That may be the end of the PM's lordly ease at the dispatch box. It was a lovely act while it lasted. Week by week we had an exhibition from another era as Cameron showed us the upper-class skill of manners being the art of making other people feel uncomfortable.

It's a great victory for Eds Miliband and Balls. They weren't quite there with the wit, humour, charm, repartee – every time Miliband tried to amuse his troops at the PM's expense he had his teeth rattled with the counter-punch. Labour leaders could see their troops being seduced, flattered and amused by Cameron – but they have now found a way through it. Not by greater charm, seduction and flattery but by playing to their strengths and being fantastically irritating.

"Dearie me," the Leader of the Opposition had said in an earlier exchange. "Dearie me." The first such usage in Parliament. It's annoying because it's so far removed from the discourse you don't know how to reply without grotesquely filthy swearing.

To every argument the PM made, Balls repeated a slow hand gesture – level to the floor and moving about a foot. "Flatlining." That began to get on Cameron's nerves. The sheer obduracy of it. You could say the previous quarter's results might make 2 per cent growth over the year. But no. Flatlining. The absolute assurance of Ed Balls, the complete sense of being right – it makes you come over all Paltrowian.

And then some accurate needling got through. Cameron was suddenly saying to a woman on the front bench "Calm down, dear", and a tiny tempest broke out. The PM had called a woman "dear". Harriet Harman's face looked like a wellington boot. Balls demanded an apology (though, Lord knows, Angela Eagle can look after herself). Miliband's teeth moved forward a good two inches and hung off the front of his face like comedy dentures.

The PM had mentioned Howard Stoate lost his seat to a Tory candidate and Angela Eagle had pointed out Stoate hadn't actually lost his seat, he'd stood down before the election.

The PM might have said, "It's always a pleasure being corrected by the hon lady" and Labour would have swooned again. But he got into this spat; he couldn't get out. He lost his place and sat down with a shrug amid the jeers and the comedy teeth, and, damnation, it looks like we're back to business as usual.