The deputy leader of the Ulster Unionist Party, Mr John Taylor, is coming under sustained British government pressure to support the party leader, Mr David Trimble, as tension mounts before Saturday's historic meeting of the Ulster Unionist Council.
While still confident of victory, sources close to Mr Trimble last night revised their forecasts for Saturday's vote on the Mitchell review package. They made clear they would be "very happy" with a 60/40 margin in favour of the devolution/decommissioning deal.
This more sober assessment, following forecasts of an "overwhelming" majority, coincides with reports of a sustained and effective campaign by anti-agreement activists within the UUP's constituency organisation.
Leading opponents of Mr Trimble's decision to enter government with Sinn Fein before any IRA decommissioning insist he could lose the vote. They cite his decision not to refer the deal to the policy-making executive as acknowledgement of a significant shift against the agreement among the party's rank and file.
Mr Trimble won the UUC's backing for the Good Friday accord with 72 per cent of the vote in April 1998.
The Sinn Fein president, Mr Gerry Adams, last night told a party meeting he was "very conscious of the wobbles, worries and concerns which are now opened up within republican activism" following the IRA decision to appoint a representative to the de Chastelain commission on decommissioning.
In a speech aimed at answering internal party dissent as well as reassuring unionists, Mr Adams said there was "no secret deal" and that Sinn Fein's public position was also its private position.
In a significant comment, Mr Adams said the IRA decision to appoint a representative to enter into discussions with the de Chastelain commission was secured as a result of the collective efforts not only of Sinn Fein and governments in Dublin and London but also of Mr Trimble.
He told a meeting of his party's ard-Comhairle in Dublin that "unionists have nothing to fear from sharing power with republicans".
About 100 Sinn Fein members listened to Mr Adams, who was flanked by senior colleagues, including Mr Martin McGuinness, Mr Martin Ferris, Mr Pat Doherty and Mr Joe Cahill.
Deaglan de Breadun, Northern Editor, adds: The 120 delegates from the Orange Order to the Ulster Unionist Council will meet tomorrow night on the eve of Saturday's critical UUC meeting. Dissident unionists hope the Orangemen will take a collective decision to oppose the deal.
While campaigners for a No vote conceded that a public meeting they organised at Omagh, Co Tyrone, this week was attended by only 16 people, they said the small attendance was a result of having to change the venue at a late stage.