It has been almost two years since Tony Blair jabbed his finger at David Cameron during one of their clashes at the dispatch box and warned him never to underestimate the power of Gordon Brown. In the political boxing ring, Mr Blair noted, Dave would always be the flyweight and Gordon the heavyweight. “However much you may dance around the ring,” Mr Blair taunted, “at some point you will come within the reach of a big clunking fist. And, you know what, you will be out on your feet, carried out of the ring.”

Well yesterday was that day. David Cameron was slaughtered at PMQs. If this surprised Mr Brown, it didn’t show. He had been up most of the night, his face as rumpled as an unmade bed. Yet he was on top of his brief (saving our economy and, of course, the global financial system). He looked comfortable in his own skin for the first time in ages. Behind him, his backbenchers roared their delight, the Labour beast back with a vengeance.

Cameron, on the other hand, certainly was surprised. Even shocked perhaps. Over the past few months he’s been fêted, lauded, petted and praised. Maybe he began to believe his own hype. Certainly, he believed it was a grand gesture – a serious, mature, statesmanlike one – to come to the Commons in the spirit of unity. His only purpose was to offer Gordo a helping hand.

Big Gordo looked at that hand, so soft and manicured, so metrosexual and, well, Etonian, when compared with his own hard-bitten stubs, and he reached for it. “I am grateful for the Leader of the Opposition’s support,” he said. “I welcome it.”

Behind him, Labour MPs were not so polite. They blame the Tories for leaks that have sent shares plunging like a barrel over Niagara Falls. Every time Dave spoke, they barracked and bayed.

“Novice!” they cried. The novice, though already unsteady on his feet, did not hit back. He redoubled his efforts to sound caring, though it was in vain, for he ended up playing Gordon’s straight man. Dave asked about small businesses and Gordo whipped out a two-page single-spaced typed statement about how he was saving them. Dave asked about “indefensible” bonuses and Gordo embarked on an almost Olympian speech about “executive remuneration”.

Dave danced some more, now trying to bash the banks. “No one wants banks to fail but also no one wants rewards for failure.”

Labour MPs sneered. It was only now that Gordo, knowing this was the last question and Dave couldn’t hit back, struck. “I do hear what you say about what you think about the irresponsibility of people in the City,” he said, almost silky, “but I have to remind you what you said on the Andrew Marr show: ‘What you won’t hear from me this week is the sort of easy cheap lines beating up the market system, bashing financiers’.”

Cue Labour pandemonium. It was an easy cheap line about easy cheap lines but they loved it. “More, more, more,” they shouted, waving order papers. Old Labour men threw their heads back, mouths wide open and howling, eyes shut, bellies shaking like giant jellies. I do hope it isn’t shown on television before the watershed.

Gordon, now sitting down, looked almost shy. It’s been a long time since they loved him so. Across from him, Dave’s moon face was a picture – hurt, disbelief, anger all travelled through. The Great Clunking Fist had done its work. Dave was down. I almost expected someone to shout “Stretcher!”

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