Mr Tony Blair hopes to signal imminent agreement on North-South structures, and the shape of the new Northern Ireland administration, during his address to the Oireachtas in Dublin on Thursday.
While a number of issues remain "in negotiation" between the Ulster Unionists and the Irish Government and the SDLP, well-placed sources last night expressed confidence that Mr Blair would at least be in position to anticipate agreement on the key areas by the end of this month. Mr Seamus Mallon, the North's Deputy First Minister, appeared to confirm this, saying: "I would hope that by the end of this week, or possibly next, things would be much clearer. Yes, decisions will be made sooner rather than later."
Mr Blair will hope to build on the emerging unionist/nationalist consensus when he arrives in Belfast tonight for the start of a crucial round of talks with Northern Ireland party leaders, before travelling to Dublin tomorrow afternoon for a packed two-day programme, the highlight of which will be that historic first address to members of the Dail and Seanad by a British Prime Minister.
Senior unionist politicians regard Mr Blair's trip to Belfast as "an entirely appropriate" gesture to Northern sensitivities in advance of a high-profile visit to the Republic. But the Prime Minister's commitment to a fresh round of diplomacy at this stage underlines the anxiety in London and Dublin that Mr Blair's address to the Oireachtas needs to do more than simply celebrate the achievement of the Belfast Agreement last April.
Agreement on the shape of the new administration in the North, the areas for North-South co-operation and the scale and remit of the Implementation Bodies would give fresh momentum to the process - keeping both governments on track to pass the necessary legislation in time for the planned transfer of powers to the Northern Ireland Assembly next February.
Crucially - with speculation continuing about the precise timing and purpose of an IRA convention - agreement on these key structures would sustain pressure on the republican movement to redefine its attitude to the question of decommissioning paramilitary weapons.
While the issue would not be "ducked", British sources last night made it clear that Mr Blair did not expect to be in a position to announce any breakthrough on it while in Dublin.
Amid growing speculation that the Ulster Unionist leader, Mr David Trimble, will finally drop his objection to a 10-member executive, UUP sources insisted any agreement on the departmental shape of the new administration would be "parked" pending IRA movement on decommissioning.
Signalling no let-up in its opposition to Sinn Fein membership of the executive without IRA decommissioning, party sources said it would be holding Mr Blair to his commitment - in his letter to Mr Trimble of April 10th - to support changes to the provisions for the exclusion of parties if they proved ineffective during the first six months of the shadow Assembly.
It is understood the UUP has until now been arguing that the proposed executive should be built largely around the six existing Northern Ireland departments - with Mr Trimble, Mr Mallon, and a number of junior ministers assuming responsibility for finance, EU affairs and the equality agenda.
However if ready to abandon that position now, it seems clear the Ulster Unionists are counting on Mr Blair to block radical Irish/SDLP proposals for Implementation Bodies dealing with EU programmes, and with Trade Promotion, Inward Investment and Business Development, which would seem to presuppose the harmonisation of tax and grant structures and the merging of industrial development agencies North and South of the Border.
Dublin is understood to have received UUP proposals for an initial eight implementation bodies. Other areas under discussion include Training and Employment, Tourism, Waterways, Fisheries, Transport, and Culture, the Arts and the Irish Language.