The British Prime Minister and the Taoiseach are set to relocate next week's make-or-break negotiations in a signal of renewed resolve to save the Belfast Agreement from collapse.
However, the Northern Ireland Secretary Dr John Reid has tabled a "precautionary" order to keep open the option of fresh Assembly elections later this year.
At the same time the possibility has emerged of a rolling series of six-week suspensions of the agreement to enable a protracted negotiation into the autumn.
At Downing Street last night Mr Blair and Mr Ahern plotted the dynamics of the negotiations which will begin with a meeting between the Minister for Foreign Affairs, Mr Brian Cowen, and Dr Reid in Dublin this afternoon.
They will then hold talks with pro-agreement parties at Hillsborough tomorrow afternoon, to prepare for the final push which will be led by Mr Blair and Mr Ahern at a venue in Britain - possibly in Birmingham - beginning Monday.
British sources last night insisted a number of locations were still being considered, and indicated Downing Street would release details this morning.
The two premiers have cleared their diaries for Monday and Tuesday, are allowing for a possible continuation on Wednesday and a likely resumption at the end of next week, probably on Saturday.
The Taoiseach's planned departure on an official visit to South America on Monday, July 16th, and Mr Blair's G8 commitment on July 20th, added to the sense of urgency as the two leaders considered their options and attempted to finesse agreed positions.
However, their readiness to lead the negotiations against the backdrop of a threatened crisis at Drumcree, and right through the climax of the loyalist marching season on July 12th, was being seen as evidence of their continuing belief they can break the decommissioning-demilitarisation-policing deadlock. "The moment of choice is here and now," Mr Blair told the House of Commons yesterday, as he resisted pressure from the Conservative leader, Mr William Hague, to exclude Sinn Fein from office should the IRA fail to commence decommissioning.
Referring to Mr Blair's letter to Mr Trimble on Good Friday 1998 promising to amend the exclusion provisions if they proved ineffective, Mr Hague pressed Mr Blair to change the law to enable the government itself "to exclude Sinn Fein ministers from the Executive if there is still no movement on arms".
Mr Blair side-stepped Mr Hague, suggesting the government already had such a power and anyway kept its options under review. "We're about to go into a process of protracted - I hope not too protracted - negotiation over how we resolve the current impasse. I don't think it sensible for me to say what we will or will not do in circumstances that may arise if that negotiation fails."
However, the Taoiseach kept the spotlight firmly on that question as he entered Downing Street, repeating his belief that fresh elections were more likely than suspension of the institutions. "Inevitably in a democracy elections are what happens when things don't work out," he said.
Supporters of Mr David Trimble expressed alarm at the emerging Irish position ahead of the negotiation. One UUP insider said: "If they signal they've no intention of suspending, then we're almost certainly not going to get decommissioning."