It now appears almost certain that the Ulster Unionist Party will sit down in a historic face-to-face meeting with Sinn Fein at Stormont tomorrow.
Senior UUP sources said last night it was "the only feasible way" for them to make the case that Sinn Fein should be expelled from the talks for breaching the Mitchell Principles. The party leader, Mr David Trimble, wanted "to give a detailed indictment".
The UUP case against Sinn Fein is likely to focus on a recent interview with an IRA spokesman in An Phoblacht, when it was said that the IRA had "problems" with some of the Mitchell Principles. Unionists are also likely to repeat their claim that Tuesday's Markethill bombing could be linked to the IRA.
However, Sinn Fein sources said they were confident the UUP bid to have the party expelled would fail. They said a similar effort by the DUP last week had been discussed and the two governments had "emerged satisfied with what was outlined".
They said Sinn Fein would be focusing on Wednesday's plenary session, when it is planned to move into substantive negotiations.
Mr Trimble said on Saturday that the UUP would not advertise its tactics and there was no "absolute necessity" to put the case against Sinn Fein in a plenary session of the talks. He said he did not even expect "any direct communication" with Sinn Fein "should we go into plenary on Tuesday".
Last night the UUP security spokesman, Mr Ken Maginnis, said it would be "sensible" to be there to put the case against Sinn Fein but it was a matter of timing. The two governments had been "somewhat tardy in responding to essential issues" which related to both decommissioning and the principle of consent.
He believed Gen John de Chastelain should be appointed to chair both Strand Two of the talks, concerning North-South relations, and the body to oversee decommissioning.
If, as is likely, Sinn Fein is not expelled from the talks, the intentions of the UUP will become clearer on Wednesday when the two governments will put forward a procedural motion to move into substantive negotiations.
Meanwhile, the Democratic Unionist Party leader, the Rev Ian Paisley, has said he plans to launch a "countrywide campaign", which will include public meetings, to put forward the DUP view of the talks. "We will be explaining to the country what really is going on up there in Stormont," he said.
Dr Philip McGarry, of the Alliance Party, said the attempt by the UUP to have Sinn Fein indicted should be viewed in the context of the party's close relationship with the loyalist parties and also with its own behaviour during the Drumcree crisis last year.
Meanwhile, the Sinn Fein president, Mr Gerry Adams, said a comment by Mr Trimble that those who said the loyalist ceasefire had been broken were only trying to score political points was deeply offensive to the victims of loyalist violence. The remark was "as contemptible as it is untrue".