British Prime Minister Mr Tony Blair is expected to resist any Irish pressure to name an autumn date for Northern Ireland Assembly elections when he meets the Taoiseach, Mr Ahern, in London this afternoon.
The Taoiseach opposed Mr Blair's decision to postpone the elections rescheduled for May 29th, and believes an early contest is the only way to break the logjam in the North's political process.
However Irish and British sources say this disagreement will not prevent the two leaders affirming their strong "in principle" commitment to an Assembly poll in late October or early November, nor undermine their efforts to "create the context" in which the elections can proceed.
London regards the early appointment of an International Monitoring Body (IMB) - to monitor paramilitary and government "acts of completion" and to oversee the implementation of the Belfast Agreement and the recent British Irish Joint Declaration - as central to creating the context in which the Ulster Unionist leader, Mr David Trimble, might commit his party to rejoin an Executive.
As reported in Monday's Irish Times, British legislation to create the IMB is ready for presentation to MPs and ministers, and officials are considering its appointment in "shadow" form while awaiting the completion of the legislative processes in Westminster and the Dáil.
However, while signed up for the principle of an IMB, Dublin is undecided as to whether the appointment of the international body should only take place in the context of a final deal on paramilitary "acts of completion".
The Irish Government's disposition on this and other matters will almost certainly turn on the assessment by Mr Blair and Mr Ahern of the latest developments within the Ulster Unionist Party, and the prospects for their resolution in a manner which leaves Mr Trimble's position as leader of pro-agreement unionism strengthened.
Sources in both capitals agreed last night that today's meeting could only provide an interim assessment of the UUP position, and identify questions to which Mr Blair and Mr Ahern would inevitably return to in September.
While the UUP's disciplinary committee has moved with surprising speed to suspend the three MPs who resigned the party whip last week, there is speculation that an appeal by the Rev Martin Smyth, Mr Jeffrey Donaldson and Mr David Burnside against any decision to expel them might not be heard by the party executive committee until September.
If they should be expelled, authoritative sources have confirmed that supporters of the three would convene another meeting of the ruling Ulster Unionist Council, probably to table a no-confidence motion in Mr Trimble's leadership.
With the three suspended MPs threatening imminent legal action, the possibility of their ultimate expulsion - and the trauma that would almost certainly trigger within the UUP - Mr Blair and Mr Ahern face the possibility that Mr Trimble's battle against his dissident wing could continue into the winter months.
With Mr Blair willing Mr Trimble to succeed in "modernising" his party, Mr Ahern faces the possibility of an eventual London conclusion that elections should be delayed until the spring or early summer of next year.
Sinn Féin and the SDLP would be expected to resist any such delay, fearing a permanent loss of credibility after the symbolically important first anniversary of the suspension of the Assembly in October. They would also be conscious that a further postponement could enhance the position of the Democratic Unionist Party.
And Mr Ahern's instinct to trust everything to an election would seem likely to grow if it appears that, despite Mr Trimble's resolution to face down his hardliners, that proves a step too far even for some of his supporters.