After eight months as Labour leader, Jeremy Corbyn is getting the hang of this PMQs business. His performance today was his best to date. He picked a subject - forced academisation - that divides both the public and the Conservative Party and relentlessly hammered away. No longer does he wastefully split his six questions between two or three issues.

Like any savvy leader, Corbyn quoted those opposed to the policy on the PM's own side. Former education secretary Kenneth Baker, Graham Brady, the chair of the backbench 1922 commitee, Graham Stuart, the former chair of the education select commitee and Tory MP Will Quince were all harnessed in support (Labour's researchers earned their keep). Corbyn's only misstep came when he cited the anxious year six pupils of Islington's Duncombe primary school.

Echoing one of Ed Miliband's most successful attacks as opposition leader, Corbyn denounced Cameron for spending £1.3bn on "a top-down reorganisation that wasn’t in his manifesto". He continued: "Even his own MPs and councillors don’t want it. Can’t he just think again?" Cameron was unable to offer any persuasive defence (the muted response from his backbenchers suggested they don't want one) and today's rise in unemployment denied him the chance to switch subject to the economy. His departing volley concluded with a cringe-making McDonald's pun (in reference to Labour's conference ban): "No wonder Labour MPs are in despair, frankly 'I'm Lovin' It'".

But the fiercest clash between Corbyn and Cameron came after the Labour leader had sat down. After the PM accused Sadiq Khan of appearing "again and again and again" with Islamist extremists, Corbyn cried: "That's disgraceful and you know it" (other Labour MPs shouted "racist"). But Cameron was not dissuaded, declaring: "Anyone can make a mistake about who they appear on a platform with ... but if you do it time after time after time it is right to question your judgement". The ferocity with which he spoke shows how the Tories intend to ramp up this charge in advance of the 5 May London mayoral contest. Though Khan enjoys a comfortable lead in recent opinion polls, Labour MPs fear that Zac Goldsmith would not repeatedly deploy it if he did not have evidence that it was working.