The British Prime Minister, Mr Tony Blair, is resisting Ulster Unionist demands for a postponement of the review of the Belfast Agreement, and has strongly supported Dr Mo Mowlam's ruling that the IRA ceasefire has not broken down.
It is understood Mr Blair made his position clear during a 20-minute telephone conversation with the First Minister, Mr David Trimble, yesterday afternoon.
The Prime Minister's official spokesman, clearly reflecting Mr Blair's attitude to the crisis now threatening to engulf the peace process, said: "The important thing to focus on is that the Mitchell review is ready to begin on Monday and he [Mr Blair] will be looking for assurances from all parties that they are committed to that review and to taking part in it."
The latest indications are that the Ulster Unionist Assembly Party could decide after all to participate in the review, albeit on its own stated terms, at a further meeting scheduled to take place on Friday morning.
Despite deputy leader Mr John Taylor's public and private opposition to participation, sources close to Mr Trimble said Assembly members "weren't in the mood for boycott" when they discussed their options at Stormont yesterday.
A backbench source later told The Irish Times: "There is no need for postponement. Either Sinn Fein are going to divvy-up or it's going nowhere."
Arguing for a direct confrontation on the decommissioning issue, the Assembly member insisted the agreement could not be saved by delay. "It's bleeding to death," he said: "If there's no product [of IRA arms], there will be no executive. It's a matter for the Provos to decide."
Mr Trimble himself, having earlier signalled his intention to press for a postponement, appeared to be falling into line with this new confrontational approach.
Clearly rejecting the outline governmental agenda for the Mitchell review, centred on the "three principles" thought to have been agreed by the parties last July, Mr Trimble later said the "prior" issue to be addressed in any review concerned the question of the republican commitment to peace.
"The question that must now be asked, in view of the behaviour of the mainstream republican movement, is, is it committed to peace and democracy?" asked Mr Trimble. "Unless we can get this preliminary question settled satisfactorily, what is the point of getting involved in a detailed discussion which is not going to end satisfactorily?"
Downing Street moved to challenge the growing impression that Dr Mowlam was somehow "isolated" as a result of her announcement on the IRA ceasefire last Thursday.
One of Mr Blair's first calls upon arriving at Chequers was to his embattled Secretary of State. His spokesman later insisted Dr Mowlam was performing one of the most difficult jobs in government "extremely well."
It is understood that senior British and Irish officials are in Washington for consultations with Senator George Mitchell about the agenda and schedule for the upcoming review, ahead of his expected arrival in Belfast on Sunday.