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Everyone expected this week's PMQs to be dominated by the government's difficulties with the abolition of the 10p rate of income tax: the media was poised, the leader of the opposition had his carefully-sharpened questions at the ready.
It did dominate, but the publication shortly beforehand of a letter from the chancellor to Treasury select committee John McFall - in which Alistair Darling promised to take steps to help those affected by the tax change - punctured the rebellion, and took much of the heat out of the session.
After tributes to Gwyneth Dunwoody, the Commons transport committee chairman who died last week, Cameron used all of his six questions to argue that this was a flip-flop.
He had plenty of good lines. The weekly session should be renamed "prime minister's U-turns", he said. The government had been forced into making "emergency announcements", "panic concessions" before coming to the Commons, performing a "backdown", "rewriting the budget", and suffering a "massive loss of authority".
He suggested the PM had backed down because he feared losing a vote on the Frank Field amendment - now withdrawn - at the committee stage of the Finance Bill next Monday, when MPs will debate the Budget.
Was this like the phantom election, Cameron asked, when Brown insisted he had decided against going to the polls despite believing Labour would win?
The Conservatives may have travelled a long way to the centre under David Cameron, but the party still cuts something of an unlikely figure as champion of the poor.
The freshly-mollified Labour benches were certainly having none of it, and Brown engaged in a rather effective tribal assault on the Tory position.
Cameron had a "new-found enthusiasm for poverty", he said, while the choice remained between "a Conservative Party that would cut incomes of the poor and a Labour Party that would increase them".
They accused each other of avoiding the "central issue". For Brown, this was that the government had done more than any other in a century to help the poor through the minimum wage and child and pension tax credits.
Cameron countered that the central issue was Brown's "massive loss of authority", referring to the humiliation of the prime minister "breaking off his talks with the president, asking for an outside line in the White House to beg with one of his PPSs not to resign".
He also delivered a fairly awful but memorable gag, in reference to Labour peer Lord Desai's description of the prime minister's leadership as "like porridge". Another week like this, Cameron said, "and it'll be Cheerios", to groans.
Liberal Democrat leader Nick Clegg also does not believe the Conservatives are sincere on this issue, and he asked the prime minister - with the apparently genuine spark of anger which is becoming his hallmark in the chamber - why he was "doing the Tories' job for them" by "penalising the poor to reward the rich".
Clegg - who was rather shamefully shouted down while offering his condolences to the families of servicemen killed in Afghanistan - followed up by calling Brown "increasingly pointless".
Labour MPs were circling the wagons around the prime minister, and Kevin Barron tapped into the party's psyche by saying that it would take no lessons from the party that closed the coal mines and put millions out of work.
London elections are now only a week away, and we saw digs at Conservative candidate Boris Johnson from Labour MPs including Dawn Butler, who gamely attempted - and fluffed - a line about Boris being "more dim witted than Dick Whittington".
Mike Gapes went on to say that Johnson was being "parachuted" into London, which seems a bit rich given that the mayoralty is hardly a safe seat, and the MP for Henley lives in Islington.
Prime minister's questions fell on St George's Day this year, and there were a smattering of roses on lapels to mark it - mostly on the Conservative benches, as far as I could see.
One Tory MP asked if the PM would make it a bank holiday, but confused the chamber by tying it in with a question about the teacher's strike on Thursday.
With Number 10 flying the flag of St George, was Brown about to give the country an extra day off?
It was, he said, a "matter for public debate". I don't think the general public would need to debate for very long before answering "yes please".
The verdict
Gordon Brown - 6/10 - U-turn on the 10p rate saved his bacon
David Cameron - 6/10 - Questions were tough despite sticky territory for the Conservatives
Nick Clegg - 6/10 - Impressive sense of conviction, but is it distinctive?
