A crucial moment in the peace process is to come tomorrow when David Trimble faces a challenge to his leadership of the Ulster Unionist party on the basis of his support for the Good Friday Agreement.
The challenge has come from the party's old guard in the form of 68-year-old the Reverend Martin Smyth, the south Belfast MP, who is an opponent of the Good Friday Agreement and is sceptical about the peace process generally.
Although he is regarded as having no chance of actually defeating Mr Trimble, his last-minute emergence as a stalking-horse represents a serious attack on party policy of persisting with the process.
Mr Smyth, a Presbyterian clergyman with almost 20 years experience in the Commons, will provide a rallying-point for those in the party who oppose the process as a whole, together with those who believe Mr Trimble should be tougher on the decommissioning issue.
Mr Smyth has the support of at least five of the party's nine other MPs. Votes will be cast by the 800-strong Ulster Unionist Council, whose sheer size makes its decisions unpredictable.
Two years ago 72 per cent of its members voted to support the Good Friday Agreement, but late last year Mr Trimble's plan to enter government with Sinn Fein without prior decommissioning was endorsed by only 58 per cent.
Mr Smyth yesterday claimed Mr Trimble had moved away from party policy by saying in Washington that he might be prepared to go into government again without guns up front, provided there was certainty of later decommissioning.
Mr Smyth said: "I think people are seeing that this is a flawed Agreement and that Tony Blair sold us empty promises about decommissioning. You can fool some of the people some of the time but you can't fool all of them all of the time."
Mr Trimble said he was "somewhat surprised and a little bit disappointed" at Mr Smyth's decision, adding: "I think what Martin needs to do is to explain to people clearly what the objective is and what policy is being pursued."
He said he hoped the contest would finally help clear the air.
Mr Smyth last night received slightly muffled support from Jeffrey Donaldson MP, who is often spoken of as a future party leader.
Mr Donaldson said he understood Mr Smyth's frustration, adding: "It is a frustration which is shared by many in the unionist community and a vote for Martin Smyth on Saturday will be a clear warning to the Government and to republicans that unionists have given enough."
Tony Blair gave his implicit backing to Mr Trimble, saying: "It's obviously a very clear choice for people and the Ulster Unionist Party will make its mind up but I have got a very great deal of respect for David Trimble and the enormous courage he has shown in trying to give people a peaceful future in Northern Ireland."