Two Democratic Unionist members of the Stormont Executive will resign their seats today, putting more pressure on the political institutions.
Mr Peter Robinson and Mr Nigel Dodds will quit their places as Mr Tony Blair prepares to host political meetings at Downing Street involving Mr David Trimble today, Mr Ahern and Mr Mark Durkan tomorrow, and Mr Gerry Adams on Thursday.
Talk of suspension and review is growing despite Mr Ahern's misgivings and Sinn Féin claims that any institution brought down will only have to be reactivated later.
With no indication that the d'Hondt mechanism will be activated to refill the two Executive posts, and the growing fatalism about the prospects for the Stormont institutions, it seemed difficult to see how the new dispensation can survive beyond Friday when the Ulster Unionist executive meets to review the Downing Street meetings and the DUP resignations.
Sources indicated yesterday the meeting between the Taoiseach and Mr Blair could be difficult.
The DUP, in an apparent change of policy, yesterday said the resignations of its ministers had been submitted to the speaker of the Assembly and would be activated if and when UUP ministers also decided to walk out.
However, in what is being seen as a ratcheting up of pressure on the UUP and amid rumours of disapproval among anti-agreement unionists, the resignations of both Mr Dodds and Mr Robinson were announced. Ulster Unionists were encouraged by the DUP to do the same. The DUP said its move would be more likely to have the desired effect and hasten the collapse of the Executive.
The move followed a day of allegation and counter-allegation at Stormont.
In the first of a series of party press conferences, Mr Trimble said the situation sparked by the raids on an alleged republican spy ring was political espionage of the gravest order. It was "10 times worse than anything that happened at Watergate".
Nationalists were sceptical of the DUP's move. The SDLP said unionists were "playing leapfrog on quicksand", while Sinn Féin claimed there was a competition among unionists as to which party was most against the agreement.
SDLP leader Mr Mark Durkan, in a reference to what was seen as the DUP tactical shift, said: "The fact is that I do not believe that resignations or bringing devolution to a halt are the way to deal with serious questions. Yes, there are serious issues there, but they are not going to be dealt with by fruitless tactics."
For Sinn Féin, Mr Gerry Kelly said: "In my opinion, there is now a competition between the DUP and now the UUP, who are now wearing the UUP's anti-agreement clothes."
In Dublin, the Fine Gael leader, Mr Enda Kenny, said: "I am calling to the parties who support the Good Friday agreement not to be pressurised into taking any precipitous actions following the resignation of the two DUP ministers from the Stormont Executive.
"This is a critical time for the peace process. The political leaders who want to see the agreement implemented should await the round of meetings being conducted by the British Prime Minister this week, after which the implications of the events of last Friday can be properly assessed."
The Labour leader, Mr Ruairí Quinn, said this was the most serious crisis since 1998. "It is a time for cool heads and calm words on all sides. It is also a time for everyone to keep their eyes on the big picture and ensure that all of the progress made over the past four years is not swept away in the welter of charge and counter-charge that we have seen since Friday."