A cabinet reshuffle has been likened to three-dimensional chess but the solitary game every Prime Minister plays is not meant to be conducted under the pressure of the clock or with incoming gunfire from your own side.
Gordon Brown, if he slept at all last night, will have to unfurl a re-shuffle that isolates his enemies and demonstrates his ability to focus on the economy, constitutional renewal and communicates that he is still in control.
A reshuffle is not the only weapon at his disposal but by losing a cabinet minister a day he has to move quickly. The question is whose loyalty can he count on and who can he placate and keep on board?
The crucial decision hinges on the Treasury where Mr Brown wants to stamp his authority and replace Alistair Darling as chancellor with his long term ally and acolyte Ed Balls, currently the Children’s Minister.
Mr Darling is said to be resistant, preferring to return to the backbenches than move to another post, in what would be a crushing blow to Mr Brown even if, as looks likely, he staggers through Friday into the weekend.
There was widespread support for Mr Darling to stay in his job given the experience he has built up over the last two years in his steady handling of the financial and economic crisis. In the next three days Mr Darling, an old friend whose steadfastness in the economic storm has not been sufficiently been appreciated by Mr Brown, could deliver the final blow.
David Miliband, who does not want to give up the Foreign Secretary post to Lord Mandelson, swore his loyalty to Mr Brown last night, a move that might leave him unable to refuse anything that the Prime Minister may now offer him.
But if Mr Brown has been held to ransom by Miliband and Darling then he will look weak not decisive and Lord Mandelson, who has been Mr Brown’s mainstay since coming back into cabinet last autumn , will be dangerously hurt not be granted his heart’s desire and be appointed to the post of Foreign Secretary.
One sure winner look likely to be Shaun Woodward, the Northern Ireland Secretary, who crossed the floor from the Tory benches and now has the ear of the Prime Minister. He might be given the Communities and local government brief cabinet seat vacated so swiftly by Hazel Blear’s Communities or even the Home Office left empty by Jacqui Smith.
But Mr Brown's limited room for manoeuvre was demonstrated when John Reid and David Blunkett, who would have come back to cabinet as retreads, were both reported to have refused offers from the Prime Minister.
Louse Casey, the specialist in anti-social behaviour, could be an outside talent appointed to the government and even Sir Alan Sugar, who visited Downing Street yesterday, was tipped for a bigger role than he currently has as a business adviser. Baroness Shriti Vadera, currently a junior business and cabinet office Minister, could see her loyalty further rewarded.
Chris Bryant, who nailed his colours to Mr Brown’s mast, could be promoted from his post as deputy leader of the Commons. For those he cannot offer patronage the support of key cabinet survivors like Jack Straw will buy the Prime Minister more time to deploy his ultimate argument to backbenchers - the fear of an early election if he is replaced.
The polling day lull that descended on Westminster bought the Prime Minister’s supporters the advantage of being able to appeal to calmer heads
One senior Scottish Labour MP, often seen as being at odds with Mr Brown, said that on consideration the idea of replacing him as Prime Minister was "crazy". He said: "For a very simple reason, whoever replaced him would have to go to the country and in an early election it is very likely that the Labour Party would not be in power."
He argued that the party’s best chance was for the fiscal stimulus to do its work and allow the economy to recover. "It’s not about love Brown or hate Brown, anyone with any loyalty to the party, the economy and the country will stick with him because the alternative is to allow the Tories to start slashing and burning the stimulus package that has stabilised the economy."