The dissident Ulster Unionist MP, Mr Willie Ross, accused his party's leadership of surrendering traditional principles in the name of pragmatism.
Mr Ross, speaking during the constitutional debate at the conference, said the "liberal influence" in the party appeared to have triumphed in recent times on decommissioning and to have "trampled over common sense".
He questioned the motives of those who said the party must be pragmatic which "in plain Ulsterspeak is `please give way' ".
Critics like himself were labelled "cynical", which meant "please stop asking hard, practical questions. We don't like the answers which may be given".
Mr Ross said if the UUP leadership had addressed hard issues like decommissioning last year or even during the summer, it could have avoided current internal tensions.
He warned that civil servants were attempting to formulate "a fudge" on decommissioning. The UUP must be part of no deception and must pursue the arms issue tooth and nail.
If Ulster Unionists deserted the principle of decommissioning "we are once again in free-fall". The conference unanimously supported a motion vetoing an executive role for Sinn Fein without meaningful and verifiable decommissioning.
Another dissident MP, Mr Willie Thompson, said the IRA would never hand over weapons and unionists must not surrender on the decommissioning issue. ein get into government, we will never get them out."
He accused the British Prime Minister, Mr Blair, of breaking his word and said unionists had been foolish to ever trust him.
A Union First member, Mr David Brewster, was prepared to lose the Assembly if that was the price for a firm line on decommissioning. "The present Stormont is not a city on a hill, it is not a new Jerusalem," he said, but added that it might give unionists "the freedom to win freedom".
The UUP's message to Sinn Fein should be clear, he said: "You are the tapeworm in the body politic and you should be flushed out."
A UUP Assemblyman and senior talks negotiator, Mr Reg Empey, said unionists should be optimistic.
For years they had complained about the lack of accountable democracy in the North and now they were on the brink of achieving their goal.
He accused the DUP and UK Unionist Assembly members of hypocrisy and said he would take their criticisms seriously when they returned their pay cheques.
A UUP Assemblyman, Mr Michael McGimpsey, said Mr Trimble should be praised, not criticised, as he had upheld the principle of consent and got rid of Articles 2 and 3 through the agreement.
The PR consultant and UUP member, Mr David Burnside, predicted the party would grow stronger as DUP and UK Unionist supporters became disillusioned.
"When Paisley falls off the shelf and Bob McCartney bores more people, they will come back into the UUP."