There were indications last night that the British government would be prepared to consider December as the date for the start of a process of IRA decommissioning, effectively a halfway point between the proposed creation of the Northern Ireland executive and the May 2000 target date for its completion.
However, the idea was immediately dismissed by sources close to Mr David Trimble, the Ulster Unionist leader and First Minister-designate, as not belonging to "the real world".
Senior Sinn Fein sources again insisted that any agreement entered upon with Mr Blair and Mr Ahern this week would not commit the IRA and would not involve any guarantee of early delivery of actual "product".
Irish sources, too, indicated their belief that the maximum concession likely from Sinn Fein would be in terms of language expressing "confidence" that the party's influence could eventually be used to help secure a resolution, but in the context of overall demilitarisation and the implementation of all aspects of the Belfast Agreement.
A senior member of the SDLP delegation raised a serious question mark over Mr Blair's proposal that the executive should fall if decommissioning was not completed by next May. Saying that this suggestion would not accord with the terms of the Belfast Agreement, the source said any "sanction" to be deployed against Sinn Fein in such circumstances would have to be found within the provisions of the text of the agreement.
A senior British source repeated that any solution must contain "the certainty of achievement and the certainty of sanction" should the IRA fail to deliver. The source added that "the Prime Minister is very serious about this deadline".