The Ulster Unionist Party has withdrawn its three ministers from the Northern Ireland Executive and says they will formally resign early next week.
If the UUP resignations go ahead, the two DUP ministers will also resign, rendering the Executive unworkable because it would not have cross-community political support.
Following the resignations, the Northern Secretary, Dr Reid, must allow seven working days to elapse before asking the Assembly to elect new ministers to the Executive, or calling a review of the Belfast Agreement and suspending the power-sharing institutions indefinitely. Dr Reid also has the option of calling fresh Assembly elections, but no-one expects him to do so.
The Ulster Unionist move to withdraw its ministers came after two Assembly motions, one proposed by the UUP and one by the DUP, to exclude Sinn FΘin from the Executive fell yesterday when the SDLP failed to give them cross-community support.
Speaking after the debate on the motions, the UUP leader, Mr Trimble, said the process of ministerial withdrawal would be "phased" and carried out in consultation with the Northern Ireland Office. He said none of the UUP ministers would attend further meetings of the Executive and would begin arrangements immediately to facilitate their withdrawal from office but he would not be drawn on when they would actually cease ministerial duties.
Earlier, opening the debate on the motions, Mr Trimble said he had been forced into his actions by the fact that for three and a half years republicans been in breach of the Belfast Agreement through the IRA's failure to decommission.
Mr Trimble said there had never been any need for violence and that republican violence "made the situation worse, they spread more bitterness in the community, they slowed down positive changes that would otherwise have happened. They've achieved nothing but to kill 3,000 people and leave a dreadful legacy. It's time they addressed the need to change and to cure that problem. "The Sinn FΘin President, Mr Gerry Adams, said he had "no doubt that the issue of weapons is a huge issue for unionists" and said great progress had been made on the issue of IRA weapons.
"This and other changes in republicanism pointed "if only [Unionists] had the vision to see it, to a future free of IRA weapons," he said.
More progress could be made if both governments and all the parties adopted a collective approach to the peace process but this would not be possible "on the terms of the DUP, UUP and British government," he said.
The DUP leader, Dr Paisley said Sinn FΘin was "associated in the lodge of international terrorism".
The peace process had seen "concession after concession," he said and "the day of concession must end".
Dr Paisley predicted the SDLP would not vote for the exclusion of Sinn FΘin as both parties were in "a process that they think will eventually bring about a united Ireland".
The acting Deputy First Minister, and SDLP deputy leader, Mr Seamus Mallon, criticised the UUP's use of members of the UVF-linked PUP to bring about the motion. In doing this it was using a party linked to violent paramilitarism in an attempt to exclude another party for the same reason. "The UUP is a proud party, it doesn't need this sort of association," he said.
Mr Mallon said his party had committed itself to removing from office those who "blatantly disregarded their decommissioning obligations". However by its own actions in not fully honouring the agreement, it was unacceptable for the UUP to call on his party to exclude Sinn FΘin from the Executive. Mr Mallon said "a heavy onus now falls on the republican leadership to undo the damage that has been done and to turn their recently emphasised commitment to decommissioning into effective action. We need deeds not words".
The newly elected leader of the Alliance Party, Mr David Ford, said by choosing to use the PUP in his motions, Mr Trimble was making the debate sectarian and accused him of "simply playing unionist politics in moving the motion".
Professor Monica McWilliams of the Women's Coalition said the IRA should no longer say they were waiting for the correct political context before decommissioning. "They have got it within their own power to set the political context themselves," she said .
Mr David Ervine of the PUP said his party had supported the UUP motion reluctantly but the unionist community was uncertain about republican intentions.
Mr Bob McCartney said he did not believe any party linked with paramilitaries should be in government. "The question is in the present tense have they shown any ability to transform themselves from terrorists to democrat? I see no sign of that," he said .
Fifty-four unionists voted for the UUP motion and 56 for the DUP motion.
In both cases 39 nationalists and six "others" voted against but as the motions failed to secure cross-community consent they fell.