Leading anti-agreement Ulster Unionists are confident they can defeat any peace deal which follows from Monday's talks between the two governments and the North's political parties.
Sources believed that if their party leader, Mr David Trimble, did bring the governments' blueprint before a meeting of their ruling body, the Ulster Unionist Council, it would be rejected.
"It is unlikely David will run with the governments' proposals," said a senior UUP source. "They will be nowhere near enough to satisfy unionists. David's room for manoeuvre is very slim. There is a good chance he won't even bring the proposals to the UUC because he will know they are a non-starter.
"Assembly elections are scheduled for May and there is growing disillusionment in our community about the current political situation. Nobody trusts Sinn Féin/IRA."
The UUC is made up of around 850 grassroots delegates. Another source said that if Mr Trimble did decide to bring the proposals to the body, even for debate, the meeting was likely to take place on March 15th, as the effective deadline for a deal is six days later.
Leading anti-agreement MP Mr David Burnside said the UUP was not prepared to consider a deal with Sinn Féin whatever peace commitments the IRA might make.
"This scum is not fit to be in government. They are not politicians. They are not democrats," he said. Mr Burnside was speaking after being told his personal details were contained in intelligence documents seized in west Belfast last week.
The discovery has been linked to the IRA. Intelligence on other unionist politicians, including UUP MP Mr Jeffrey Donaldson, was also found.
Mr Burnside said the British Prime Minister's efforts to obtain a deal were pointless: "Blair is wasting his time. There is no way unionists should consider any sort of deal with Sinn Féin, irrespective of their commitments.
"The IRA intelligence on me was current and up-to-date. There will be no deal because their word is a lie. Blair may be conned but unionists will not. Blair is acting tough on Iraq but he is being suckered by the IRA and Sinn Féin. His double standards are amazing."
Meanwhile, the annual general meeting of the UUC takes places in Belfast today. It is expected to be low-key.
All party officers are up for re-election but UUP sources are confident Mr Trimble will face no challengers.
While Mr Trimble might not be elected unanimously, anti-agreement unionists have ruled out the possibility of someone from their ranks standing against him.
Mr Trimble's speech to today's meeting is expected to be hardline and to set the tone for Monday's talks.
"David will be putting the pressure firmly on Sinn Féin to make concrete commitments on decommissioning," said a party source.
"The UUP has taken enough risks during this process. There will be no more leaps of faith. Somehow, after Stormontgate, Sinn Féin has managed to get themselves in a position where they are making demands which it appears might be fulfilled."