Mr Gerry Adams has called for a concerted British, Irish and US initiative to drive the Northern Ireland peace process forward.
The Sinn Fein president has starkly defined the risk inherent in the ongoing impasse, saying bluntly: "If people don't keep to the commitments that are made then we don't have an agreement."
Mr Adams was speaking after more than an hour of talks with Mr Tony Blair at 10 Downing Street, during which he pressed the British Prime Minister to oblige the Ulster Unionist leadership to move swiftly to create the executive and North-South ministerial council prescribed by the Belfast Agreement.
While senior UUP sources last night insisted Mr David Trimble was not coming under pressure from London, Mr Adams said he would be very disappointed if Mr Blair "does not accept the challenge this represents".
With attention beginning to turn to Mr Blair's address to the Dail on November 26th, Downing Street said the Prime Minister stood ready to do whatever it took to keep the process moving forward.
But before yesterday's meeting Sinn Fein sources again insisted there was no possibility of IRA agreement to start decommissioning.
Mr Adams dismissed as "nonsense" weekend reports that the issue would shortly be put to a special IRA convention. Such reports, he claimed, were designed "to confuse and to make our task rather more difficult."
Confirming again the so far irreconcilable republican and unionist interpretations of the Belfast Agreement, Mr Adams said the IRA was not required to decommission.
Pressed by reporters on the issue, he went on: "The very fact that the IRA has taken its weapons out of commission, is on cessation and is maintaining that cessation - despite killings by loyalists, despite the activities of the British forces on the ground, despite the refusal of the unionists to honour their commitments - I think is proof of the good will of the IRA to make this peace process work."
The agreement was a charter for change. "To be a vehicle for change it needs an engine. That engine is not there at the moment. We cannot make progress on the British occupied part of Ireland unless the British are in leadership all the time on this issue encouraging, cajoling, nudging the process forward."
There was, he said, "a creeping concern within the broad nationalist/republican constituency that the refusal to keep to the deadlines, establish the institutions . . . is eroding and corroding confidence in this agreement and its ability to deliver."
Resuming his theme that delivery could not be a matter for unionist decision, Mr Adams said anyone expecting unionism to reach a decent deal with nationalism would have to wait "a very, very long time indeed . . . because unionism from its own perspective has all sorts of reluctances, all sorts of hesitations, in moving forward into a new shared future."