There are two vital debates being staged in the Commons this afternoon - one in public, the other in private.
The first is over calls for an enquiry into the Iraq war. The second is likely to determine the result of the first, and will take place between Labour MPs, their whips, their friends and their consciences. It can be summed up simply - does my anger over the war in Iraq outweigh my political hatred of a coalition of convenience between the Nats and the Tories.
My guess is that for enough of them the answer will be that it doesn't, and that the government will win the day .