British ministers fear they could be forced into a second suspension of the Belfast Agreement in the aftermath of the forthcoming general and local elections in Northern Ireland.
This became clear last night as Mr David Trimble and dissident Ulster Unionists appeared to converge on next month as the effective deadline for IRA decommissioning.
At the same time The Irish Times has learned that the UUP leader and First Minister is set to resume talks in Belfast tomorrow on a possible electoral pact with the Alliance Party leader, Mr Sean Neeson.
Mr Trimble stopped short of Mr Jeffrey Donaldson's demand that next month should mark an "absolute" deadline for decommissioning or the UUP's withdrawal from the Executive when he appeared on the BBC's Breakfast With Frost programme yesterday.
However, he said he would be looking to the British and Irish governments and the SDLP to "honour their undertakings" and "show that republicans are not going to be able to destroy the process".
Sources close to the UUP leader subsequently told The Irish Times: "June is the date. It's impossible to see us getting through the month without substantial progress on decommissioning."
The latest indication of Mr Trimble's thinking came on the anniversary of his agreement last May to re-enter the Executive on the back of the IRA's promise to put its weapons verifiably "beyond use".
It also came amid growing evidence that Mr Trimble and his anti-agreement opponents have called an uneasy truce ahead of elections which could have profound implications for the future of the UUP and Mr Trimble's leadership of it, as well as for the agreement.
Despite the present uneasy internal peace, leading anti-agreement figures privately suggest that Mr Trimble could face a renewed leadership challenge at the annual meeting of the Ulster Unionist Council, rescheduled for June 23rd.
The British Prime Minister, Mr Tony Blair, is expected to go to Buckingham Palace tomorrow or on Wednesday to seek a dissolution of parliament and clear the decks for a June 7th poll. In that event, final results from Northern Ireland's district council elections, to be held on the same day, will probably not emerge until the following Tuesday, June 12th.
If the election outcome places Mr Trimble's leadership under pressure there will be an extremely narrow 10-day period for the two governments to attempt to bridge the gap between the conflicting demands of the Ulster Unionists and Sinn Fein on the unresolved issues of policing, decommissioning, demilitarisation and the ban on Sinn Fein's participation in meetings of the North-South Ministerial Council.
British and Irish ministers are hoping that a successful campaign for Mr Trimble will buy time and ease the pressure for immediate resolution of all these issues just as the loyalist marching season approaches its climax.
However, sources close to Mr Trimble say that his determination to force the decommissioning issue is actually rooted in his belief that the UUP will fare well in the general election.
British sources last night insisted that suspension of the agreement would be "absolutely a worst-case scenario". However, ministers have privately confirmed their fear that the election results might leave them with no alternative.