Tensions were rising in Ulster Unionist ranks last night as details began to emerge of the "deal" which the British and Irish governments believe can resolve the decommissioning issue and permit the creation of the power-sharing executive later this week.
The Irish Times understands that the key elements of the proposed deal would provide for:
an unequivocal acceptance by republicans of the obligation to secure decommissioning by May 2000;
the appointment of the executive as early as tomorrow;
a devolution order in the House of Commons next week, stipulating a September date for the formal transfer of powers;
a report the same month from the International Commission on Decommissioning, setting out agreed procedures and a timetable for decommissioning;
the first phase of actual decommissioning in late November or early December;
further decommissioning, with the process to be completed by May 2000, or the suspension of the Belfast Agreement and a review in accordance with the provisions of the Good Friday text.
There was distinct, but still very cautious, optimism in both the British and Irish government camps last night that an eleventh-hour deal could be reached ahead of Mr Blair's midnight deadline.
However - amid strong suggestions that Mr David Trimble could face the defections of at least six Assembly Members - there was uncertainty as to whether the UUP leader could agree an effective six-month gap between the creation of the executive and a promised start to actual decommissioning.
Conversely, it was being stressed that any prospect of firm commitments to decommissioning by Sinn Fein would, from its point of view, depend on the executive "going live" immediately, rather than in "shadow" form until September.
Official sources at the talks said: "Most of the day was spent on Sinn Fein. The governments think they have a deal on that side and they are trying to sell it to Trimble." However, while the UUP leader's demeanour was encouraging, his bottom-line position was still unclear.
It had been hoped at one stage that negotiations might even be concluded yesterday but Mr Trimble's consent to this could not be secured and there was concern that he had fallen back to his original demand for prior decommissioning. However, the governments were said to be holding firm that this was not contained in the Belfast Agreement.
Senior political insiders said Sinn Fein had taken a "helpful" attitude in negotiations.
Despite the positive spinning on behalf of both governments, ahead of Gen de Chastelain's report, there was still considerable uncertainty as to whether Sinn Fein would deliver commitments as explicit as those being sought by London and Dublin.
That gap between expectation and delivery was starkly underlined last night by Mr Trimble who insisted, on leaving Stormont, that any commitments would have to be given by Sinn Fein on behalf of the IRA.
Some key players believe Sinn Fein will express "confidence" that it can "succeed" in using its influence to secure decommissioning in the context of the implementation of the agreement and the successful establishment of its institutions.
Whether that would prove either deliverable - or sufficient for the Ulster Unionists - remained unclear last night as some attention focused on the role of Mr Jeffrey Donaldson MP, the leading dissident who rejoined Mr Trimble's talks team just last Friday.
Mr Donaldson had a lengthy meeting with Ms Liz O'Donnell and senior Irish officials, and this was being interpreted as a positive indicator. However, he was last night sticking to his demand for actual decommissioning before the executive could be formed.
And it is understood that, before he accepted Mr Trimble's invitation to rejoin the team, the Lagan Valley MP stipulated clearly that this attitude would also extend to any shadow executive.