Stay tuned for live coverage of PMQs from 1200.
1200: Brown stands up, and offers his condolences to the soldiers and policeman murdered in Northern Ireland over the past few days. He commemorates the peace marches in NI today, calling them "unity against violence".
1201: First question from Andrew Miller: "When will the banks get their act together to stimulate demand for, not just vehicles, but for other manufactured goods?" Gives Brown an opportunity to talk about his "international settlement" for banking.
1202: Cameron gets a big cheer. He thanks the Speaker and PM for what they said a fortnight ago, on the occasion of the death of his son, Ivan.
1204: Cameron leads on the situation in Northern Ireland, calling the attacks "disgusting". Asks Brown whether everyone is working together to ensure that the killers are brought to justice. Brown assures him that it is.
1205: It's a sombre, non-combative PMQs so far. Cameron continues: "The Prime Minster is absolutely right about this unity."
1207: Brown says that the Government will support the police and armed forces, bringing things round to the atrocious demonstrations by Muslim extremists in Luton: "Homecoming celebrations should be what they are meant to be ... There is a right to freedom of speech, but there is not a right to disorder and disruption."
1209: I've never heard the word "agree" come up so much in PMQs. The tone of this encounter is quite unlike most you'll ever see. Cameron now turns to the Binyam Mohamed case, asking whether Brown is satisfied that he knows enough about what's happened.
1210: Brown: "We do not condone torture."
1212: Cameron's getting more heated now. His point is that an inquiry into the claims of Binyam Mohamed, while welcome, is too specific, and won't deal with the more general issue of the UK's involvement (or not) in rendition and torture.
1213: Peter Hain says that we should be "encouraged" by how Northern Irish politicians have responded to the terror attacks.
1215: Clegg offers his condolences for the killings in Northern Ireland, and welcomes Cameron back to Parliament. Then asks Brown whether Sarkozy's NATO announcement means that France and Britain can work with each other to lead European defence.
1217: Brown says that he's talked with Sarkozy about what the UK and France can do together in Afghanistan, but he continues: "We've got to remember that we've talking about the British Army, the British Air Force and the British Navy. And we should always be able to make our own decisions."
1219: Backbench questions now. Sir Nicholas Winterton calls for greater Parliamentary scrutiny of Brown's measures to deal with the economic crisis. Too right. And also pushes Brown on what's being done for savers.
1220: Brown brings it all round to "Tory cuts".
1221: Question on regional airports.
1222: David Simpson (DUP) recounts his visit to the home of the murdered Northern Irish policeman, Stephen Carroll. Urges Brown to pledge that everything will be done to catch the constable's killers, and that nothing will allow NI to slip back into the Troubles. Brown replies that "there is a determination to do everything in our power to bring what are clod-blooded murderers to justice".
1224: A blast of Old Labour vitriol from Harry Cohen, asking why banks have to be run privately. Brown uses the opportunity to run through his banking insurance schemes.
1226: Question on a bus pass scheme in Chesterfield.
1227: Big pantomine cheer for Dennis Skinner. He bangs on about Lib Dem councils, bus passes and wasted money.
1228: A perfect opportunity for Brown to push one of his favourite dividing lines. A Tory MP (I missed who) asked what the PM has "bought due to the VAT cut". Brown responds that only the Tories could "scorn" an attempt to help "hard-working families.
1230: Question on the policing environment in Northern Ireland.
1231: And that's it. Expect my verdict shortly.
VERDICT: I'm not going to judge which party leader came out on top - because none of them did, or really tried to. Today's PMQs was a sombre, non-combative affair. It seemed right, on this occasion, and an example of Parliament at its best.