A full-scale summit is being held in London today as efforts to secure agreement on the future of the peace process reach a climax ahead of an expected announcement of elections to the Belfast Assembly.
Sinn Féin President Gerry Adams, Ulster Unionist leader David Trimble, the Irish Taoiseach, the British Prime Minister and their respective negotiating teams are gathering in Downing Street.
The talks will attempt to secure sufficient agreement which would result in November elections leading to a functioning Executive and Assembly.
There has been speculation that while a broad agreement on the way forward for the process is possible, a historic breakthrough to complete the implementation of the Good Friday Agreement remains unlikely.
Mr Ahern and Mr Blair are meeting privately first and later they will join negotiatons with Mr Adams and Mr Trimble.
There have been intense and extended exchanges between Mr Adams and Mr Trimble in Belfast over the weekend, and the governments appear keen to sustain the momentum in London.
The Ulster Unionist Party is demanding a complete end to IRA activity as the price for their commitment to power-sharing in the Stormont administration.
A deal would mean the UUP would be required to contest the elections on a pro-Agreement manifesto, a radical change for the party after years of efforts to frustrate the peace accord.
But Republicans are wary that the talks might yet be strung out or undermined in a bid to again avoid the twice-cancelled election in which Sinn Féin is expected to make gains and the Ulster Unionists are expected to fare poorly.
November 13th remains the preferred date for Assembly elections, although there have already been suggestions that the poll could be put back by up to three weeks, beyond which the start of the Christmas holiday season would make an election unlikely.
British government officials have sought to play down expectations thst a date for the Assembly elections will finally be announced.
Mr Blair's official spokesman said: ``Today is a day for assessment rather than decisions.
``We have seen the quietest summer for 30 years in Northern Ireland in terms of trouble, and also the most intensive period of negotiation between some of the parties since the Agreement itself.
``The building blocks are there for a possible deal which would allow us to go into an election in a positive frame of mind. But the work is not yet done,'' the spokesman said.
``So today is about assessing where we are, how far along the road we have got, but the context is a positive one and we clearly hope to build on that.''
The spokesman added: ``Everybody is aware that time is short and we don't have too much longer to play with.''
On his way to the Downing Street meeting Mr Gerry Adams repeated his party's belief that elections will be called soon.
There had been speculation that today's talks would be ``make or break'', he said but insisted: ``In fact they are a continuation of the very intensive discussions we have been involved in back home with some of the other parties and the two governments.''
Those discussions had covered issues such as policing, the human rights agenda, the equality agenda and demilitarisation. All of those were as yet ``incomplete''.
Asked about the issue of arms, Mr Adams said that while this was a matter for the armed groups, the issue of creating conditions in which arms can be put beyond use was a matter for all the parties.
The way it was done was an issue for the decommissioning body and the armed groups, he added.
UUP leader Mr David Trimble told reporters as he arrived: ``We are hopeful that some progress can be made.
``We all know what the issues are. The issues are the same issues that we were considering in April: whether there is going to be an end to paramilitary activity, whether Republicans are going to resume and this time deal effectively with the decommissioning issue, and whether, as a result of that, it is going to be possible for the Assembly to resume and for elections to occur.''
US president George W. Bush's special adviser, Ambassador Richard Haass, today delayed a visit to the North to participate in the crucial peace process summit.