Andrew Gimson sketch picLast week Ed Miliband managed to become “an insect with an excruciatingly painful sting“. This week he reverted to being the kind of insect that drones in an annoying way but does not actually hurt you. By the fourth time he accused David Cameron of being a mere spokesman for the energy companies, Miliband had begun to sound monotonous.

Not that when it comes to monotony, the Prime Minister is prepared to concede any kind of advantage to the Leader of the Opposition. Cameron shouted his way through this half hour. He never employed the still, small voice of calm: the statesmanlike tone of someone with the self-possession to rise above mere partisanship and take the nation into his confidence.

It is true that the House was in a highly partisan mood. As MPs watched to see whether Miliband could repeat his triumph of last week, they made an awful lot of noise.

And that noise sounds far louder when you are in the Chamber than when you watch the encounter on television, as I did, having escaped Westminster on a half-term visit to Edinburgh.

Perhaps the small screen made Cameron’s bellowed indignation seem even more disproportionate. He behaved like a man who is still feeling sore after Miliband’s jibes of last week.

In one of his more successful sallies, Cameron pointed out that Miliband has switched electricity companies: “He switched his supplier! Yes, he went for one of these insurgent companies…He adopts Tory policy to help his own family!”

This story could have been used to expose Miliband as a ridiculous hypocrite. It was instead employed to make him appear a disgraceful scoundrel: an exaggeration, surely, of what Cameron himself thought. A more relaxed Prime Minister might have welcomed Miliband’s private conversion to the policy of switching supplier, and regretted that such common sense is forgotten when the Labour leader decides what to say in public.

There was an undertone of relief when the Prime Minister accused Miliband of promoting “less choice, less competition, higher prices”, and concluded: “It’s the same old Labour.” How anxious the Tories are to believe that this is true.

Cameron accused Miliband of asking “not one question” about the economy. This was a bit unfair: energy prices are an aspect of the economy. But it is true that Miliband seems to have little to say on such questions as economic growth and unemployment.

How contemptuous the Prime Minister sounded as he said of the Labour leader: “He’s a one-trick pony and he’s run out of road.” Once again, this remark suffered by being needlessly exaggerated. Cameron and Miliband are engaged in a two-horse race, which either of them could win if something really bad happens to the other horse. To display such an open lack of respect for his main competitor sounded a bit unsporting, and also a bit imprudent.