With Michael Gove demoted after he became too toxic for the Tories, and wage growth at its lowest level since ONS records began in 2001, Ed Miliband arrived well-armed at the final PMQs before the summer recess. He had the best of the opening exchanges on these subjects, asking Cameron why he had moved the Education Secretary after previously promising to keep him in his post for years.
But midway through the session, Cameron produced a far more potent weapon in the form of a Harriet Harman quote on tax. During her new LBC phone-in show on Monday night, she said:
Yes, I think people on middle incomes should contribute more through their taxes.
As Labour sources have been quick to point out, Harman was referring to the principle of middle earners paying more than lower earners in a progressive tax system, but the comment was easily spun by Cameron as a call for a tax rise on the "squeezed middle".
He declared: "One of the things that wasn't noticed and happened yesterday, the Deputy Leader of the Labour Party, on the radio said this, and I want to quote it very precisely: 'I think people on middle incomes should contribute more through their taxes.' That is what she said ... There we are, that is their policy. The squeezed middle will be squeezed more. Now he needs to tell us which people are going to pay which taxes."
Miliband, who was clearly unaware of the remarks, was thrown off his stride, while Harman responded by shouting "It's true!", only adding to the Tories' glee. From that point onwards, the PM was in control, with Miliband left only to accuse him of "desperate stuff". The session ended with a boisterous Caemeron declaring: "Everyone can see the contrast, in this party, the leader reshuffles the Cabinet. In his party, the shadow cabinet desperately want to reshuffle the leader."
After the session, Miliband's spokesman (who was also unaware of the quote) accused Cameron of being "deeply dishonest", adding that "he knows this is not our party's position". He reminded journalists that Labour has pledged to cut taxes for 24 million middle and low income earners by reintroducing a 10p rate of tax, and made it clear that it is not proposing any tax rises for this group.
But while true, this fall shorts of the categoric pledge - "we will not raise taxes on middle earners" - that Miliband will now be pressed to make. Unless he does, this will remain a potent attack line for the Tories.