The development, while not considered fatal to the party's participation in talks, is nonetheless seen as a potentially ominous sign of dissent within the party's most senior ranks.
The party leader, David Trimble, who in September led the party into talks in the same building as Sinn Fein, has regularly given pessimistic assessments about the prospect of agreement there. But he clearly favours their continuation and can be expected to resist the pressure to pull out.
The expression of anti-talks feeling follows threats to withdraw from Stormont emanating from the smaller Progressive Unionist party, which complains that "the British government have courted the IRA but they have not done anything for us". PUP representatives last night met the Secretary of State for Northern Ireland, Mo Mowlam, in Belfast, to press for accelerated releases of loyalist prisoners.
The four Unionist MPs who advocate withdrawal from the talks are William Ross, William Thompson, Roy Beggs and Clifford Forsythe. None of them is regarded as being among the party's front-line leadership and none is a member of the party's team.
They have however received a measure of support from another MP, Jeffrey Donaldson, an important member of the talks team, who said that he would suggest reviewing participation in the talks unless the government desisted from what he described as a steady stream of concessions to republicans.
A letter from the four MPs was sent to the party's chief whip, the Rev Martin Smyth MP. The 10-strong parliamentary party, while clearly an important organ, shares power and influence within the party with the Unionist council, the executive and the talks team.
Some of the IRA's most notorious bombers are among 161 terrorists leaving Northern Ireland's Maze prison on Christmas home leave today in a move which has outraged victims.
Paul Kavanagh and Thomas Quigley, who were convicted of the bombing of Chelsea barracks, and Brighton bomber Patrick Magee are among the prisoners who have been granted 10 days leave to spend with their families. Magee, 46, was branded "a man of exceptional cruelty and inhumanity" by an Old Bailey judge and given eight life sentences in 1986.Reuse content