Mr David Trimble was under renewed pressure last night as the British Prime Minister and the Taoiseach delayed publication of proposals designed to end the political deadlock threatening the Belfast Agreement.
Irish officials were travelling to Co Durham ahead of Mr Ahern's scheduled meeting with Mr Tony Blair in his Sedgefield constituency this morning. However, British sources insisted the meeting would not mark "the end of the story" - signalling that the eagerly awaited proposals were now unlikely to be presented to the Northern Ireland parties before Sunday at the earliest.
The sources maintained the delay did not spell any sense of crisis or breakdown, but the need rather for Mr Blair and Mr Ahern to give further thought to the management of the next stage in the process, and, in particular, the need to give the parties time and space to consider the proposals before their wider publication.
However, a sense of brinkmanship was growing last night as a Sinn Fein source suggested the political stalemate could drag into the autumn and be followed by fresh Assembly elections, while Mr Trimble was being urged to abandon the current process altogether.
As aides to Mr Trimble digested the implications of that call from Ulster Unionist MPs Mr Jeffrey Donaldson and Mr David Burnside, it became clear the UUP leader was on a potential collision course with Mr Blair over the proposed package of measures in at least two critical areas, over and beyond the question of further proposed policing reforms.
On policing, the Ulster Unionists and senior Conservatives in London say they will resist any move - within the parameters of the Patten Commission proposals, or beyond - which would reduce the power and accountability of the Secretary of State for Northern Ireland, or impair the "operational independence" of the Chief Constable.
UUP sources yesterday declared their anxiety on two further counts:
1. Whether the publication of the British proposals would be conditional on assurances that the IRA would reciprocate with a significant move on weapons decommissioning, and
2. Whether the British government shared their view that decommissioning under the remit of the International Decommissioning Commission would require actual destruction of weaponry.
Sinn Fein sources rejected this interpretation, and accused the Ulster Unionists of resiling from the concept of putting weapons beyond use, agreed at the Hillsborough negotiation in May last year.
When pressed on the issue, British sources would say only that it was best left to Gen De Chastelain to decide if his criteria had been met.
While it seemed unlikely that the emergent British proposals would seek to be prescriptive on the decommissioning issue, the sources said any package "has to deal with all the issues in the round".
Mr Trimble - who is due to return to Northern Ireland from Canada tomorrow - suffered a hammer-blow when Mr Donald son and Mr Burnside said they would no longer support the ongoing negotiations to sustain the institutions of government established under the Good Friday accord.
In an important statement last week Mr Trimble hinted it might not be possible to implement the agreement and that other possibilities would then have to be considered.
Barring a significant breakthrough on IRA decommissioning, party sources suspect Mr Donaldson and Mr Burnside will take their alternative agenda to yet another meeting of the Ulster Unionist Council.