The Taoiseach and the British Prime Minister are again on standby for a possible visit to Belfast to advance negotiations designed to secure the Belfast Agreement.
Authoritative sources confirmed that Mr Ahern and Mr Blair could travel back to Northern Ireland this afternoon. However, it was being made clear in Whitehall last night that a decision by Mr Blair to travel would signal only that "a deal is possible" and not that an agreement on decommissioning, demilitarisation and policing had already been concluded.
A decision on a fresh prime ministerial initiative is likely to turn on the outcome of resumed talks between senior British and Irish officials in London this morning.
The Irish Times understands that central to those talks will be Sinn Fein's response to the latest draft proposals formulated by the officials in talks at Downing Street yesterday.
While previous "deadlines" have come and gone, the effort to break the deadlock is believed to have been given added urgency by the imminent departure of the First Minister, Mr David Trimble, and the Sinn Fein president, Mr Gerry Adams, for separate engagements in the United States.
The flurry of diplomatic activity has raised alarm within the Ulster Unionist Party about the possibility of a behind-the-scenes agreement between London and Sinn Fein on the vexed question of policing reform.
Unionist sources say the British government has assured Mr Trimble there will be no amendment to the controversial Police (Northern Ireland) Act, implementing the Patten Commission reforms of the Royal Ulster Constabulary.
Much of the ongoing London-Dublin negotiation is believed to centre on the bid for British assurances that key republican concerns on policing would be addressed by the Labour government in the legislative session following its expected general election victory.
Usually reliable British sources say a "big picture deal", which would liberate the process from "the recurrent series of crises", is possible, while insisting there is still no guarantee of success. Central to the British approach is that all parties must have credible assurance "that their concerns will be addressed in a meaningful way".
Irish sources appear to take it "as read" that any agreement will include an IRA commitment to re-engage with the International Commission on "modalities" for decommissioning, and to a subsequent specific "act" of disarmament.
However, it remains unclear whether the two governments have secured republican agreement that such an act would come before the British general election, expected in May.
There is scepticism also in unionist and other circles as to whether Sinn Fein or the IRA will accept the concept of a programme of (British) demilitarisation directly linked to ongoing IRA decommissioning over a period of years.