Suzanne Breen outlines what's next for the North's political institutions afterthe latest crisis at Stormont
What are unionist ministers at Stormont likely to do over the coming days? The North's First Minister, Mr David Trimble, has told the British Prime Minister he will withdraw his ministers from the power-sharing Executive if Mr Blair does not send a motion to the Assembly on Monday to exclude Sinn Féin.
If Mr Blair fails to respond, Mr Trimble will resign as First Minister on Tuesday along with Ulster Unionist Environment Minister, Mr Dermot Nesbitt; Arts Minister, Mr Michael McGimpsey; and Economy Minister, Sir Reg Empey. The resignation of the DUP's two ministers - Regional Development Minister, Mr Peter Robinson, and Social Development Minister, Mr Nigel Dodds - comes into force tomorrow.
What are the options for the British government in response to the current political crisis?
Mr Blair and the Northern Secretary, Dr John Reid, have four options.
They can send a motion to the Assembly on Monday to exclude Sinn Féin as Mr Trimble wishes.
They can allow Mr Trimble and his colleagues to resign on Tuesday and then dissolve the Assembly and call fresh elections.
They can suspend the Assembly and the Executive and announce a review of the Belfast Agreement with the Assembly elections, which are already due to take place next May, going ahead as planned.
They can also do the latter but decide to indefinitely postpone the elections until the parties reach agreement during review negotiations.
What is the British government likely to do?
The option of excluding Sinn Féin from government is a non-runner. Any successful vote in the Assembly would need cross-community support and the SDLP will not give it. Besides, the motion would create such enmity in Sinn Féin ranks that political progress would be extremely difficult.
Most observers also believe it unlikely the British government will allow Mr Trimble and his ministers to resign, then dissolve the Assembly and call fresh elections. This is the DUP's favoured option and will not meet resistance from Sinn Féin. Both parties expect to make significant gains.
What are the advantages and disadvantages of imminent elections?
The DUP says the spirit of the legislation which set up the political institutions means there should be dissolution and elections in the present circumstances. It accuses the British government of running scared of democracy.
Downing Street and some pro-Agreement politicians believe the likely result of elections would be highly damaging for the peace process.
Sinn Féin and the DUP would emerge as the two largest parties and thus be entitled to the positions of First Minister and Deputy First Minister in a new administration.
Sources say this would be an unworkable scenario and no deal is realistically possible with DUP and Sinn Féin dominance.
So is the Assembly's suspension and a review of the Belfast Agreement most likely? Yes. And how long will this last? Dr Reid is likely to opt for an open-ended suspension which allows the parties a non-time limited period to reach a new deal.
In theory, the Assembly could be suspended for 10 weeks or 10 years. However, a lengthy suspension would cause the institutions to lose considerable credibility in the community.
Nationalists are against suspension, which they see as the British government allowing unionists to hold the political process to ransom. However, Mr Blair will argue it is the lesser evil and offers the only chance of breathing life back into the process. A review of the Agreement would be established soon after suspension with all the parties invited to bilateral and round-table talks.
Will it work? The British government will say similar problems were overcome in the past and the Agreement remains the only show in town.
The DUP says that, without prior elections, it simply will not take part in any review which will be "aimed at patching up a failed process".
Some observers fear a review would be meaningless until after elections. No party would be prepared for compromise in negotiations with a future poll looming.
What effect would suspension have on the political institutions in the North?
If Dr Reid suspends the Assembly, all devolved power would revert to Westminster. Assembly members would remain in office but the Assembly would not meet or carry out any functions. The Executive would also cease to meet. The work carried out by its 12 ministers would fall to Northern Ireland Office ministers. Assembly members would still continue to be paid. But their normal salary of £43,000 would likely be reduced by over a third to £29,000.
The North-South Ministerial Council meetings would also stop during suspension.