The three MPs are taking legal action
Three rebel Ulster Unionist MPs have begun a High Court action to challenge their suspension from the party.
Jeffrey Donaldson, the Reverend Martin Smyth and David Burnside are seeking an injunction to overturn the decision of a party disciplinary committee to suspend them.
They were suspended last week after resigning the party whip at Westminster in protest at the policies of UUP leader David Trimble.
During a brief opening to the case on Thursday in Belfast, a QC for the three MPs compared their suspension from the party to "a dark doing in the backroom of a UDA pub, rather than what one expected from a modern-day political party".
A barrister appearing for the Ulster Unionist Party said the remarks were uncalled for.
The hearing was then adjourned until Friday afternoon.
They want the court to rule that the party officers' action, before a disciplinary hearing takes place on 17 July, was illegal.
A writ has been issued against party officers, including Sir Reg Empey and Lord Maginnis, but not the party leader.
Solicitor John McBirney, acting for the three MPs, said the writ also sought injunctions restraining the officers from "interfering with the MPs in the exercise of their rights and duties as party members, and from allowing a disciplinary hearing to go ahead".
The writ also challenges the make-up of the disciplinary committee and questions the role of the chairman, Raymond Ferguson, a solicitor in County Fermanagh.
Mr Donaldson has sworn an affidavit challenging the chairman's impartiality on the grounds that Mr Ferguson has "consistently and forcefully" expressed his opposition to the Lagan Valley MP's views on party policy.
The MPs quit the whip in a move designed to increase pressure on Mr Trimble by refusing to endorse his policy on the British-Irish joint declaration.
It is the latest wrangle within the Ulster Unionist Party.
Last month, dissident unionists gathered 30 signatures for a motion of no confidence in David Trimble as Member of Parliament for Upper Bann.
Upper Bann sceptics press ahead with action against Mr Trimble
The motion, due to be discussed on 8 July, was tabled following the latest row between Mr Trimble and Mr Donaldson.
A similar party vote in the Lagan Valley constituency against Mr Donaldson was dropped "in the interests of party unity" following his narrow defeat in a vote taken by the UUP's 900-strong ruling council.
In June, Mr Trimble narrowly fended off a challenge from party rebels, led by Mr Donaldson, who wanted the party to reject the recent British and Irish joint declaration.
The joint declaration, released in May, outlined plans to reduce troop numbers to 5,000 as part of an attempt to move the Northern Ireland political process forward.
It included five annexes dealing with security normalisation, policing and justice, human rights and equality, on-the-run paramilitaries and mechanisms to verify and monitor any deal.
Northern Ireland's devolved administration was suspended last October amid allegations of IRA intelligence gathering in the Stormont government.