The meeting, which is scheduled for next Saturday, will be asked to endorse the deal thrashed out by Mr Trimble and the Sinn Fein president, Gerry Adams, under the chairmanship of the former United States senator George Mitchell.
If Mr Trimble prevails at the meeting, the way will be cleared for the formation of a new cross-community executive including his party and Sinn Fein. Some of those involved in the peace process say this could take place as early as 29 November. If so, this would amount to an extraordinary burst of activity after more than a year and a half of setbacks. Earlier this week, Mr Mitchell recommended that the IRA should appoint a go-between with the decommissioning commission on the day that the executive was formed.
The Ulster Unionist leader, launching what he predicted would be a short but momentous campaign after a meeting of the party officers, said he was sure of winning a significant endorsement.
Even as he spoke at a media conference, however, there were ominous noises off. One of his opponents among the officers, David Brewster, growled at the back of the room: "I think it's about time we had a bit of honesty in this party." His remark, which was broadcast live on BBC Radio Ulster, came just after Mr Trimble's assertion that he was confident discussions would take place "in a civilised manner".
Within hours of this, Derek Hussey, one of the two deputy whips of Mr Trimble's Assembly party, stepped down from the post, saying the proposals had presented him with a dilemma over his election manifesto commitment.
The Unionist leadership and the anti-Trimble faction are expected to lobby hard during the next week to rally the many uncommitted party members to their standards. With 800 or more delegates entitled to attend the meeting, its exact outcome may be unpredictable.
Mr Trimble said he regarded this week's statements by Sinn Fein and the IRA as "for the first time a real step forward", adding that he was confident the deal provided the basis for both devolution and the decommissioning of paramilitary weapons. He added: "Our aim is to transform our society from one based on the use or threat of force to one based solely on the democratic process. The disarmament process and the establishment of the institutions are essential elements in achieving this objective.
"There is a mood in the country which realises that this is the time to break the stalemate, this is the time to get things going. There is a hunger out there for the new administration we are about to form."
Jeffrey Donaldson, the UUP MP who is a prominent member of the anti- Trimble camp, contradicted his leader on the importance of the republican statements, saying they did not offer the clarity or certainty that the IRA would decommission. "The package on offer from the IRA is inadequate," he said.
Big business backed Mr Trimble, however. Nigel Smyth, director of the Confederation of British Industry's Northern Ireland section, said: "We are confident that this represents the best deal available. There is absolutely no alternative. This is the best deal that can be negotiated and that is why we are backing David Trimble."
This was echoed from the trade union side by Tom Gillen, of the Irish Congress of Trade Unions, who said: "We are now on the threshold of a historic happening in Northern Ireland."
t The decision in August by the former Northern Ireland secretary Mo Mowlam that the IRA ceasefire had not broken down was lawful, a judge ruled yesterday. Mr Justice Kerr rejected an application for judicial review made by Michelle Williamson, of Belfast, whose parents were killed in the IRA's 1993 Shankill Road bombing.Reuse content