Senior figures close to Mr David Trimble say he has "almost certainly fought his last election as leader" of the Ulster Unionist Party.
The UUP leader and First Minister was in Downing Street yesterday afternoon urging the British Prime Minister, Mr Tony Blair, to "re-calibrate" his Northern Ireland policy and stop "rewarding" extremists.
He repeated his threat to force a crisis for the Belfast Agreement and its institutions if the IRA failed to move on decommissioning by the end of this month.
However, as Mr Trimble played down the scale of his party's losses in the district council elections, well-placed party sources said he could still face a direct leadership challenge from the Rev Martin Smyth or Mr Jeffrey Donaldson, or both, at the rescheduled annual meeting of the Ulster Unionist Council on Saturday week.
In the aftermath of the DUP's general election advance, the view emerging among some of Mr Trimble's own supporters is that he should stay in place to conclude the negotiations that will determine the fate of the Belfast Agreement.
The Irish Times has been told that at some point thereafter, and whatever the outcome of the negotiations, Mr Trimble is expected to make way for an alternative leader who might reunite his party.
These pro-agreement sources calculate that the party will reject any attempt to reopen the leadership question in advance of Mr Trimble's July 1st deadline for a substantial IRA move on decommissioning, or his resignation as First Minister.
They also believe Mr Trimble could defeat any challenge by Mr Smyth, despite the fact that the South Belfast MP won 43 per cent of the vote in his first attempt to topple Mr Trimble last year.
However, there is continuing speculation that Mr Donaldson might enter the fray.
Sources close to the Lagan Valley MP say he would be "extremely reluctant" to challenge Mr Trimble, but he had not ruled anything in or out at this point.
Mr Donaldson's policy position is considerably more complex than media coverage sometimes allows.
Although classed as an "anti-agreement" dissident, he has repeatedly said he would be happy to see the Stormont Assembly and Executive survive provided the IRA decommissioned its weapons. And he is known broadly to support Mr Trimble's intention to bring the issue to a head by July 1st.
One cynical view being canvassed yesterday was that Mr Donaldson might make his own leadership bid for fear either that Mr Smyth might win or that delay could facilitate the emergence of the South Antrim MP, Mr David Burnside, as a future rival for the crown.
However, it seems likely that Mr Donaldson's eventual decision will turn on the party inquest into its Westminster and council election reverses.
After his meeting with Mr Blair yesterday, Mr Trimble said there should not be any room for manoeuvre at all in terms of a situation in which the agreement imposed a clear obligation on paramilitaries to disarm and where promises made by the republican movement 13 months ago had not been kept. Mr Trimble's own highly limited room for manoeuvre was starkly underlined by his colleague, Mr Burnside, who appeared to rule out the permanent sealing of arms dumps already opened to inspection as a possible way out of the decommissioning deadlock.
The newly elected South Antrim MP suggested that the Sinn Fein president, Mr Gerry Adams, would make such a declaration in respect of one arms dump as part of a republican move to force fresh concessions from London on policing and demilitarisation.
"It is a con job which won't wash," he insisted.
Following the Downing Street meeting, Mr Burnside also revealed that he had told Mr Blair the UUP wanted the name and insignia of the Royal Ulster Constabulary to be restored.