The stand-off between the SDLP and the British government over policing continued last night despite Mr Peter Mandelson's warning that it could spell "calamity" for the peace process.
The Northern Secretary urged the party not to "torpedo" the process. He made it clear the party would bear the responsibility if key reforms of the RUC had to be delayed.
Mr Mandelson's intervention followed earlier Whitehall warnings that reform of the RUC could be put on ice unless the SDLP swiftly endorsed the alternative Police Service of Northern Ireland.
His comments reflected the British government's growing fear that Mr David Trimble might find it impossible to remain in the Executive unless the SDLP at least gives its backing to the new police service.
While declining to comment directly on that possibility last night, the First Minister and Ulster Unionist leader said: "It's up to the SDLP, they know what needs to be done. It would be immoral for people to be in government and making laws and withhold support from those who have to enforce them."
With Mr Mandelson pressing for an SDLP commitment to serve on the policing board, it seemed clear last night the board would be the first casualty of any significant delay in the reform programme.
Mr Mandelson has made the necessary arrangements to bring the board into being in "shadow" form later this month. However, failure to see it begin its operations could in turn hit the first wave of 50/50 Protestant-Catholic recruitment for the new service, scheduled for late March.
It could also affect the timetable for the formal change of title planned for September. It is unclear whether any effective moratorium on the Patten reforms would affect plans to phase out the existing Full Time Reserve or increase the Part-Time Reserve.
Mr Mandelson said he was not trying to "bounce" the SDLP into a decision. But he said the only thing which could delay implementation of the planned reforms would be a nationalist refusal to join the policing board.
Speaking on BBC Radio, he urged the SDLP to "travel on the basis of trust that we are getting it right", adding: "I think it would be more than a crying shame, it would be a calamity, if that central part of the Good Friday agreement . . . were to be held up until we cross every T and dot every I."
However, SDLP Assembly member Mr Alex Attwood insisted: "There remain substantive issues that will convince or not convince the nationalist and republican community that the new beginning is to be realised."
He continued: "If the SDLP goes onto the policing board and the nationalist/republican community does not go into the policing service, then we would have a worse outcome than many others."
The Taoiseach, during an official visit to Malta, spoke about Northern Ireland matters by telephone with the British Prime Minister for 15 to 20 minutes yesterday afternoon.
Government sources said both leaders were "anxious to inject a sense of urgency into the process" and they "took the opportunity to map out what needs to be done in the period ahead".
Irish officials are to meet their British counterparts in London today as part of the resumption of intensive contacts and discussions.
Earlier, Mr Ahern said he had discussed Northern Ireland issues at length with Mr John Hume and Mr Seamus Mallon of the SDLP when he met them on holidays in Spain last week.
The "three difficult areas" continued to be decommissioning, demilitarisation and the Patten report. "We had made some progress before Christmas, but not enough," he said.