The crisis in the peace process deepened last night as the Ulster Unionist Party issued a blunt warning that it would not change its position on decommissioning before, during or after next month's European election.
With the future of the Belfast Agreement thrown into question by Mr Tony Blair's "absolute" deadline of June 30th, Mr Trimble last night further raised the stakes - with a direct challenge to the British Prime Minister to state whether, in his government's view, devolution of power could proceed without the start of "actual decommissioning".
The Ulster Unionist leader met Gen John de Chastelain, the chairman of the International Decommissioning Commission, in Belfast yesterday, to establish whether he shared his understanding that "progress" to be reported before the June 30th target date for the transfer of power meant "actual decommissioning" would have begun.
Mr Trimble refused to comment on the meeting, while confirming that he had "put the question to the government" in a written summary of his Assembly party's response to the proposals understood to have been agreed with the other leaders during last Friday's marathon 10-hour negotiations at Downing Street.
Mr Trimble's summary of the UUP position was given to Number 10 yesterday morning, and is certain to form the basis of a tense meeting between Mr Blair and Mr Trimble when the prime minister returns from the Balkans some time on Wednesday. That meeting will be crucial in determining whether to reconvene last Friday's talks involving the Irish Government, the SDLP and Sinn Fein.
Despite the effective rejection of Friday's proposal to break the decommissioning deadlock by the UUP Assembly party, Mr Blair is determined to continue to force the pace in the negotiations.
However the scale of the challenge now confronting him was underlined by a UUP statement clearly intended to reduce the risk of an all-out rebellion in Mr Trimble's ranks. The statement reaffirmed the leadership's commitment to the full implementation of the Belfast Agreement, recognising that "it must be protected in terms of its democratic and moral integrity". It continued: "The agreement specifies that all parties, including those linked to terrorist organisations, must demonstrate their commitment to exclusively peaceful and democratic means. This means there must be a credible and verifiable start to a process of decommissioning, before Sinn Fein can participate in government".
Some observers wondered if the statement's reference to the "start to a process" was intended to leave open the possibility that the leadership might yet be amenable to statements providing assurances about future republican intentions. However, there seemed little doubt that the statement, is sued by party headquarters, was a direct response to deepening internal criticism of Mr Trimble's conduct of last week's negotiations.
The statement said: "The agreement and the Mitchell report are crystal clear on this issue [decommissioning] and those who signed up to the agreement are obliged to implement it in its entirety. Every aspect of the agreement has been implemented or substantially progressed except for decommissioning. It is incredible to expect that an executive can be set up whilst this issue has not been satisfactorily and finally resolved."
In a point of clarification, the statement added: "The Ulster Unionist Party will not change its position on this matter now, during or after the European election. The issue goes right to the heart of the agreement and to the commitments to peace and democracy that government ministers must abide by."
The statement also confirmed, as reported in yesterday's Irish Times, that Mr Trimble "did not present the government's proposal as a final or agreed text to the Assembly members on Saturday. The proposal was incomplete and clearly insufficient in terms of clarity or substance."
In Dublin, the Government expressed disappointment at last night's UUP statement. Earlier, the Taoiseach, Mr Ahern, asked Mr Trimble to accept a "pledge" from him that he would ensure all aspects of the Belfast Agreement - particularly those crucially important to the unionists - would be implemented.
Further discussions between British and Irish officials and the Northern parties continued yesterday. A Government spokesman said it was disappointing that the formula agreed on Friday to "get round the problem" had not been accepted by the UUP.
Last night the Sinn Fein president, Mr Gerry Adams, said there was an urgent duty on Mr Trimble to spell out publicly why he said he did not present the proposal as a final or agreed text to the UUP assembly on Saturday.