The Taoiseach and British Prime Minister are expected to travel to Hillsborough later today for an intensive effort to find an agreement that could restore the Northern Ireland Executive.
The main focus will be on devising a new formula which, without actual IRA arms up front, would provide the UUP leader, Mr David Trimble, with the "clarity and certainty" he requires to convince his ruling Ulster Unionist Council that IRA violence is a thing of the past.
However, Mr Ahern and Mr Blair will make their final decision on whether to travel only this morning, based on the outcome of detailed discussions in London yesterday between Irish and British officials, in consultation with Sinn Fein and the Ulster Unionist Party.
The officials spent yesterday refining a series of draft statements which, if agreed, would be issued in a sequence that would lead to the restoration of the suspended political institutions.
The Irish officials flew back to Dublin last night to brief the Taoiseach, and are understood to have told him that some progress has been made.
Government sources yesterday described the Downing Street talks on Tuesday as "a good day's work", and said yesterday's drafting session in London, conducted in consultation with Sinn Fein and the UUP, had built on that.
The talks now centre on efforts to agree a series of statements similar to the sequence that led to the setting up of the political institutions late last year.
A first statement would come jointly from the Irish and British governments, outlining how the remaining aspects of the Belfast Agreement, such as police reform and demilitarisation, were to be implemented.
This paper would also outline how the issue of paramilitary weapons decommissioning should be dealt with, and would detail a mechanism for the restoration of the Executive, Assembly and North/South bodies.
Under the plan being considered, a second statement would come from the IRA with the intention of providing the Ulster Unionist Party with the "clarity and certainty" it has been seeking on the decommissioning issue.
Finally, the Ulster Unionist Party would declare that the statements from the governments and the IRA provided the basis for its participation in restored political institutions.
However, major differences remain on the key issues. The parts of the proposed joint government statement dealing with police reform, demilitarisation and the arms decommissioning issue have not been agreed.
On RUC reform, it is understood that the UUP has pushed hard this week for a watering down of the British government's stated intention to implement the Patten report on RUC reform in full.
In the absence of the prospect of actual decommissioning taking place in the short term, a clear IRA statement of assurance that its weapons will not be used is seen as vital.
However, it is not clear what is the minimum IRA commitment that would be acceptable to the UUP. On the other hand, there are doubts about whether the IRA will consider issuing any statement at all. Republican sources say Sinn Fein leaders will not even consider going to the IRA to seek such a statement unless they are certain it will guarantee the restoration of the institutions.
Despite this stepping up of the political push for a resolution, sources in both governments yesterday played down any expectation of an early breakthrough.
They insisted the two days of talks did not indicate that there was a weekend deadline or target date, and said it was quite possible the talks would continue next week.
Both governments are anxious to avoid the "hothouse" atmosphere of several past failed efforts to resolve the decommissioning issue.