The Rev Martin Smyth is still being tipped as the most likely direct challenger to Mr David Trimble's leadership at next Saturday's meeting of the Ulster Unionist Council.
Mr Smyth gave the clearest signal last night that he would prefer and support a leadership bid by fellow MP Mr Jeffrey Donaldson. And sources close to the Lagan Valley MP told The Irish Times that possibility was "not yet ruled out".
However, the focus behind the scenes remained on continuing talks designed to persuade Mr Trimble to step down voluntarily and make way for a Jeffrey Donaldson/Reg Empey "dream ticket" leadership team.
In a statement yesterday Sir Reg, Enterprise Minister in the Northern Executive, said he had no intention of challenging Mr Trimble. Well-placed party sources insisted that did not rule out the "dream ticket" option, however, since its advocates want to give Mr Trimble space to quit the leadership following his threatened resignation as First Minister on July 1st.
"The point is there is no question of a challenge," said one source. "We want David to go of his own accord in the interests of party unity."
Mr Trimble has given no indication that he intends to stand down. His decision to include Mr Donaldson in his team for Monday's talks with the British Prime Minister, Mr Blair, and the Taoiseach in London is intended to reinforce his message to both leaders that he will carry through his threat to resign unless there is a significant IRA move on decommissioning.
A potentially huge complication for Mr Trimble, however, is that Dublin anticipates new legislation to meet outstanding republican and nationalist concerns about policing as part of any overall deal.
There is also anxiety on the part of both governments that Sinn Fein's approach in the next fortnight may be influenced by the perception that Mr Trimble's days may be numbered whatever the outcome of the upcoming negotiations. One senior unionist told The Irish Times: "It's no longer just a matter of the guns. The message on the doorsteps was that we simply weren't believed. We need to rebuild the party and regain our credibility."
Party loyalists say Mr Trimble's strong card for next Saturday's meeting is that - because of his post-dated letter of resignation - unionists only have to wait another week to see whether or not the IRA intends to start decommissioning. And they remain confident he will beat off any challenge by Mr Smyth.
As he urges his party to hold its nerve, however, Mr Trimble will also be dismayed by threats by some of his own supporters to splinter-off into a new party should he lose the leadership. Yesterday's Boston Herald reported Mr Duncan Shipley Dalton as saying the idea of a breakaway by some pro-agreement unionists at Stormont had been discussed. The South Antrim Assembly member reportedly told the newspaper's editorial board: "There's a lot of us in the group who follow him. Our loyalties are to him rather than the party."
Suzanne Breen, in Belfast, adds: There were strong indications last night that Mr Donaldson is seriously considering a leadership challenge to Mr Trimble next Saturday. Sources said Mr Donaldson would have to decide this weekend whether to stand against Mr Trimble.
Speaking after a meeting of the UUP's executive last night, Mr Smyth said he did not think he would be mounting a leadership challenge. But he said there might be others who would attempt to oust Mr Trimble.
He wouldn't be surprised if Mr Donaldson's chance for the leadership came "sooner rather than later", he said. "I wouldn't rule out a challenge to the leadership from different sources within the party."