Alan Johnson: will he be leader?

The bookies’ favourite will not want to be seen wielding the dagger, which explains why the Health Secretary came out behind Gordon Brown publicly yesterday. Behind the scenes his ambitions are clear, with allies pointing out that, unlike three years ago, he is ready for the top job. As well as ensuring that he is not damaged by any coup, the priority for those around Mr Johnson will be to make certain that no other candidates come forward.

James Purnell: will he carry the dagger?

The question swirling round Westminster yesterday was whether Mr Purnell, bearer of the Blairite torch, will do anything to jeopardise Mr Brown’s reshuffle. The Work and Pensions Secretary could be the one to strike against the Prime Minister by deciding to be difficult and turning down any job offers. He might, for instance, refuse to serve as Home Secretary — a job he is not keen to do because he sees himself as too instinctively liberal.

Harriet Harman: will she keep her current job?

The priority for Labour’s deputy leader is likely to be to ensure that she keeps her job under Mr Brown’s successor. She has repeatedly ruled herself out for the top job and there has been a strong “Stop Harriet” campaign in place inside the Labour Party for more than a year. She says publicly that she has never had any intention of running for the leadership, and it is not clear that she would get the backing. So her priority will be to reassure whoever emerges as the front-runner that she could represent continuity in the party. It is not entirely clear that she would be able to do so without a vote.

Ed Balls: can he keep Mr Brown in office?

The Schools Secretary has signalled that he is interested in holding Labour’s highest office. However, the chances of him stealing the crown if it now becomes available are not high. It is in Mr Balls’s best interest to shore up Mr Brown’s position for as long as possible. Mr Brown is likely to do favours for his longest-serving and most loyal apparatchik. And with the Chancellorship within his grasp, holding one of the “Big Three” offices of state could be his ticket to yet greater things.

Jack Straw: what will the greybeard with influence do next?

A year ago Mr Straw thought that he could be leader if Mr Brown stood down suddenly. This belief seems to have waned in recent months. Having largely forsworn personal ambition, he will be watched closely to see how he jumps in the coming days. His primary goal will be to continue to hold a senior government position, and any public hint that he is supporting Mr Johnson would be hugely significant. Worth watching to see how often — and how convincingly — he comes out in support of Mr Brown over the next week.

Lord Mandelson: can he keep the Brown Government together?

Since his appointment in October, Lord Mandelson has been a lightning rod for Mr Brown’s Government, drawing the heat and light out of the sometimes angry Blairite mob. Never will this role be more necessary than over the next five days. If he does his job well, he could end up as the next Foreign Secretary.

Alistair Darling: is he the man who could wield the dagger?

The Chancellor’s future rests on a knife edge after Mr Brown referred to him in the past tense on Monday morning. But mistreating Mr Darling — who has been a loyal servant at Mr Brown’s side for many years — could misfire spectacularly. He is letting it be known that he would walk out of government if removed from the Treasury. Would he do such a thing and then turn on Mr Brown? Any hint of an attack from Mr Darling could well prove fatal.

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