Of all the calculations being made by Labour MPs, the easiest to work out are those of the traditional Labour left. Secure in Labour’s heartlands, never reconciled to the New Labour project, these grizzled remnants of the old Bennite wing of the party are beyond the reach of the whips. For these men of the North - and they are, for the most part, men and from the North - personality never enters into it. For them it is all about policy. Their preference is for ideological purity. We are talking about unreconstructed class warriors who would rather go down fighting the good fight than countenance anything as grubby as a compromise with electoral reality. For them, the maths is easy. They will pocket what they can in the way of concessions on policy and then watch as Brown leads the right of the party to defeat at the election. At which point the balance of power in the party will shift decisively in their favour.

For the ultras on the Blairite wing of the party, the logic is very different, though as straightforward. Defeat will be seen as a repudiation of everything they have worked for. For them, the prospect of continuing with Gordon Brown is unthinkable. So we are left with that great swathe of MPs in the middle; the survivors of the 1997 and 2001 intake that make up the bulk of the parliamentary party: pragmatic men and women of the centre, schooled in the art of compromise. Sitting on wafer-thin majorities in marginal constituencies, these are the MPs looking most nervously over their shoulders. And yet somehow, inexplicably, they have thrown their lot in with Mr. Brown. Just what is going on here? How to explain it?

Two theories are currently doing the rounds. The first suggests that this great mass is no more convinced that Brown can win the election than the next man. Convinced that the election is lost whenever it comes, and whoever is in charge, they are simply looking to secure another year’s pension contributions and salary before the inevitable defeat. Doubtless some are so minded, but this is the business end of the party, the place where deals are done, favours traded, and where the whips go to work and so a second theory suggests the great mass of MPs in the centre were still biddable, still willing to be led, but simply lacked direction. This is the calculation the Brownites made and so, in the shadows, Nick Brown and his of gang of cajolers, wheedlers, arm-twisters and thugs went to work, knowing that the support of these MPs was crucial. Lose it and it was all over for Brown.

They appear to have been proven right. They were biddable. Although they have been bought off extremely cheaply. Some were lucky enough to secure themselves a government job. Most settled for much less. A perfunctory mea culpa,vague noises about a less confrontational style and a promise to reconsider some aspects of policy was enough to send them scurrying out in front of the waiting TV cameras, newly energised, waxing lyrical about the prospects for renewal and even victory.

In truth, it was a sorry sight and will have convinced no-one. The whole thing smacks of indecision and, ultimately, of cowardice. My guess is that, had a cabinet member signalled his intention to stand, Brown would not be in the leadership today. Had Alan Johnson dropped the faux modesty for a minute I think the party would have rallied to his call. I think the Labour backbenches were willing – in many cases, desperate - to be led. I think had the cabinet matched word and deed, they could have wrested back control of their fate. But none did. And so, like lemmings, they follow Brown over the edge of the cliff.