Cameron, the king of the mood swings, was on typical form today. He veers between calmness and rage with alarming rapidity. The pattern is always the same. He deals reasonably with Miliband’s opening questions but the mercury starts to rise at around Question Four, and his temper reaches straitjacket level on Question Six.

He called Ed Miliband and Ed Balls ‘the two muppets’ for mismanaging the Royal Mail while in office. Their bungling cost the exchequer billions, he said. And they didn’t dare privatise the firm for fear of antagonising angry posties and union bosses.

Miliband accused Cameron of flogging the company cheap to enrich the Square Mile. At today’s valuation it might have raised an extra £1.4bn.

Cameron sounded a bit sheepish. ‘Shares are trading ahead of where they were sold,’ he conceded. And Miliband produced evidence of a capitalist plot. A cabal of favoured investors had made a ‘gentlemen’s agreement’ to retain their shares but they flogged them as soon as the price spiked.

Bankers not gentlemanly? Well I never.

Oddly the Royal Mail plays well for both leaders. They can indulge in the cartoon-strip politics that passes for debate. Miliband becomes a plastic gonk being tossed from one trade union thug to another. And Cameron is portrayed as a double agent of City financiers sent into politics to drain blood from the poor and use it to made black pudding for fatcats.

The distortions really took hold when Miliband hinted that the fire-sale was unnecessary.

Cameron leapt in. ‘A privatisation no one wanted!?’ he yelped. ‘But it was in the Labour manifesto.’

Behind him the Tories went off like a minor earthquake. The two Eds shook their heads at each other. Subsequent research revealed that Labour’s manifesto carried no promise of a sell off. All too late. Damage done.

Cameron calmed down during backbench questions. But as the session drew to a close the red mist rolled in.

He was asked about sick Taffies fleeing Welsh hospitals and throwing themselves on the mercy of English doctors.

‘A scandal!’ raged Cameron. He blamed Labour for cutting NHS funding in Wales. Then he spotted something.

‘Why is the opposition leader laughing? If he had any backbone he’d get hold of the first minister and tell him to start investing.’

A query about tuition fees caused another detonation. Cameron quoted a Miliband promise to publish his tuition fee policy ‘this year.’ But that was in 2010.

‘I know he’s got an empty head and a blank sheet of paper,’ snarled the pit-bull, ‘but he really ought to get on with it.’

It’s lucky Cameron’s already got the top job. If he were in opposition, critics would accuse him of lacking dignity and composure and ‘not looking like a prime minister.’

His best and most bitter dig at Miliband was over alleged splits within Labour.

‘They’re weak and warring,’ he said. ‘No wonder they’re looking for a new team.’

The idea that plotters are preparing the condolence books and choosing the hymns for Miliband’s memorial service will greatly hearten the Tories. And it should send a bolt of fear through Labour’s ranks

Were Miliband bound for Number 10 he ought to be cresting the zenith of a large poll-lead by now. But the party leaders are neck and neck. And one neck is on the block.

Tags: David Cameron, PMQs, Royal Mail