The outcome of tonight's Downing Street meeting between the Taoiseach, Mr Ahern, and the British Prime Minister, Mr Tony Blair, is expected to determine whether round-table talks hosted by the two governments should be held tomorrow or Friday.
With the negotiations still deadlocked sources said the most that could be expected of tonight's meeting would be some formula, which in the absence of an interlocking deal on policing, decommissioning and demilitarisation, would help safeguard the institutions of the Belfast Agreement.
Efforts could focus on trying to persuade the IRA to re-engage with Gen John de Chastelain's decommissioning body in return for a pledge from the First Minister, Mr David Trimble, to lift the Ulster Unionist sanctions on Sinn Fein.
This could be an effective admission that the remaining policing difficulties cannot be resolved ahead of the Westminster and local elections.
One senior talks insider said that without agreement on policing it was unlikely that Mr Trimble would remove his veto on Sinn Fein ministers attending North-South Ministerial Council meetings.
"I think the most we can hope for is some form of soft landing," he said. This could amount to a review of the agreement without actual suspension of the Assembly and Executive.
However, against a general pessimistic political mood, one senior British source was prepared to insist that there could still be life left in the negotiations.
He said that as well as policing, further detail was required from republicans on what the IRA might deliver in terms of putting its arms beyond use if there was a deal.
Tomorrow night's meeting was important and would determine whether further talks, possibly on Friday in Belfast or Hillsborough, would serve any useful purpose, he said. "People shouldn't rush to write this off at this stage," he added.
There is considerable internal debate in the SDLP over whether in the event of its demands on policing being met it should endorse the new service and act independently of Sinn Fein.
The SDLP Agriculture Minister, Ms Brid Rodgers, said last night that a deal could still be achieved on all the issues, including policing. The process could not be held back by any one party, she said, without specifying whether she was referring to Sinn Fein or the Ulster Unionists.
"The great leap forward on all the outstanding issues of policing, weapons, watchtowers and vetoes of the workings of the government can be achieved. The process cannot be held captive to any one party or interest. The governments can move it on conclusively," said Ms Rodgers.
Meanwhile, the Sinn Fein president, Mr Gerry Adams, said the controversy over former IRA prisoner Brian Keenan's remarks in south Armagh on Sunday were a "storm in a teacup".
The senior republican, Mr Keenan, said: "The revolution can never be over until we have our country, until we have British imperialism where it belongs - in the dustbin of history."
Mr Trimble called on the republican movement to repudiate Mr Keenan's remarks.
Mr Adams said the response to Mr Keenan's remarks were entirely contrived.
