William Hague told delegates at the annual Tory conference at Blackpool that his commitment to the Good Friday Agreement was undiminished but this did not extend to the release of paramilitary prisoners.

"Eighteen months after the signing of that agreement, the apparatus of terror is still intact, violence continues and not one gun or bomb has been dismantled or been given up.

"I say that until that changes no more terrorist murderers should be released from jail."

He responded to calls by Liberal Democrat leader Charles Kennedy not to speak out against the government on its handling of Northern Ireland issues.

"I say when murderers are being released on to our streets in direct contravention of assurances given to the people of Northern Ireland and contained in the agreement itself, it is the absolute duty of the leader of the Opposition to raise his voice in protest.

"God save us from the spineless crawling to the government of liberal politicians."

Mr Hague backed the accusations made by the shadow NI secretary Andrew Mackay that the government had broken assurances to the people of Northern Ireland.

BBC NI Political Correspondent, Mark Simpson:"Tories intend to maintain pressure on Government"

Mr Mackay said the prime minister had made promises prior to the Good Friday Referendum which he had not delivered upon.

"Regrettably Tony Blair has said one thing and done another, he has betrayed the trust of the people of Northern Ireland."

Mr Mackay said the prime minister did not have a blank cheque on Northern Ireland and insisted he would continue to attack Government policy on Northern Ireland whenever Tony Blair made mistakes.

He said that the Conservatives would oppose in Parliament any changes which the party felt would undermine the RUC including proposals to change the name and emblem of the force.

David Trimble optimistic about NI review at Tory conference

Ulster Unionist leader David Trimble received a standing ovation from delegations when he arrived on the conference platform for the start of the Northern Ireland debate.

Speaking at a fringe meeting on Wednesday night, he said: "If we manage to make progress and get over present problems and get things moving in the way that I would like I don't think the problem we've is going to come back again, because society is changing."

These comments were in sharp contrast to a prediction by Ulster Unionist deputy leader John Taylor. He believes the current review being chaired by former US senator George Mitchell is doomed to failure.

The Ulster Unionists are holding their annual conference at the weekend in Enniskillen, Co Fermanagh, the location in 1989 of one of the worst IRA bomb atrocities.

Sinn Fein was invited to a fringe meeting at the conference, but the invitation was withdrawn last week.