Stay tuned for live coverage from 12:00
Memory for Michael Foot and the four servicemen who have been killed in the last week.
12:03: And we're off. Tory backbencher Richard Benyon wants assurances that soldiers serving overseas receive a postal vote. Brown gives him such.
12:05: Here's Cameron. He starts with the examination into the deaths of soldiers in Afghanistan which suggests that inadquately strong motorised equipment was responsible for their deaths. Prepare for Brown's Chilcot evidence, contradicted by Lord Guthrie among others, to come under sustained attack. Brown is at his most vulnerable on defence. That said, Brown apologises for the defence minister who suggested that the deaths had nothing to do with the Snatch Land Rover, which I think is a first.
12:08: Cameron quotes the former defence chiefs who described Brown's Chilcot evidence as 'disingenuous' and 'dissembling'. Some Labour backbenchers call Guthrie et al 'Tories'. This puts Brown on the backfoot and he refuses to distance himself from members of his party who have questioned the loyalties of those who have served Britain. Cameron is angry; it's compelling. Brown dissembles. He's on the rack, waffling about 'assurances'.
12:10: Cameron says that Brown hasn't the character to stand up to his own backbenchers. Cameron demolishes Brown's defence record, citing a number of officers and civil servants of all ranks who have condemned Brown. 'Why are they wrong and he's right.
12:12: This is getting very heated. Brown says he won't take moral lessons from Cameron after Ashcroft. They really hate each other; it's palpable.
12:13: Brown lays a Brownie that Defence budgets have risen year on year - the cut in the essential helicopter budget says otherwise. Brown says the only people that cut Defence were the Tories in the 90s. Cameron retorts that the reason the Tories did that was because the Tories had won the Cold War, no thanks to those who donned CND badges, gesturing to the government front bench. Cameron attacks Brown's chronic underfunding through lack of appropriate planning when committed to two wars.
It's not very dignified, but it's quite a spectacle. Cameron wins, he always does on defence, but the force is lost amid the noise and politiciking.
12:13: Brown hopes to reverse the rout, suggesting that Ashcroft is proof the Tories haven't changed. Arguably, he has a point, but Labour is just as culpable with Lord Paul and they've had 13 years to right the wrong.
12:15: Here's Clegg on the baleful crime figures and he makes a good point that under Labour it is clear that prison isn't working. Game, set, match Clegg. Brown argues that the Lib Dems' proposals about cutting CCTV are would not help. Cameron should have mentioned Grayling's vindication yesterday.
12:22: Tory Richard Bacon on the IED threat and the findings that Snatch Land Rovers were ill-equipped to deal with the threats of the Afghan war.
Brown says that MoD is given assurances by staff of airworthiness, road worthiness etc prior to be deployment. That is the case now, not then. All very well being wise after the event.
12:25: Labour veteran left-winger David Winnick asks about the CIA using torture and Mi5's complicity, another blot on Brown's premiership.
12:26: PLANT ALERT. This is brave: Brown attacks the Tories over cutting the aircraft carriers. He wants cross-party consensus. There isn't even government consensus on this issue. Brown is right though, the carriers are probably essential if Britain is to project power and defend its interests, interesting that they will be built in part in his constituency though.
12:30: Ann Winterton asks a sensible question about maintaining 0% VAT on food, clothes and books. A question that applies to the Tories as much as it does to Labour.
12:32: Norman Baker wants the railways to waive their RPI =1 fare arrangement. Good point. As the railways have never carried as many passengers and freight, surely they could reduce their fares.
VERDICT: A noisy and childish spectatcle throughout, the exchanges about Michael Foot being or not being a supporter of the USSR particularly. Brown is at his most vulnerable on defence and Cameron won the exchange. But the victory was pyrric - for instance the Cold War jibe was chirlish. Nick Clegg was more direct and incisive. The whole event will likely put people off Westminster.