Mr David Burnside has been chosen by the UUP branch in South Antrim as the constituency candidate for the next British General Election.
He defeated the party leadership's choice, Mr Jim Wilson, the UUP chief whip in the Assembly, at a selection meeting last night. Mr Burnside secured 96 votes to Mr Wilson's 50 votes in the second count of the four-cornered contest.
Mr Burnside said he was pleased to have received votes from across the party. The Belfast Agreement had gone "too far towards the republican side. People want a more balanced approached," he said.
Mr Wilson said he accepted the party's judgement and he believed the party leader, Mr David Trimble, would not be too disappointed.
However, Mr Duncan Shipley-Dalton said the party had effectively resigned the seat to the Rev Willie McCrea of the DUP, who defeated Mr Burnside in the September by-election for the seat.
Meanwhile, Mr Trimble has warned of "inevitably negative consequences" if progress is not made soon on paramilitary disarmament and policing.
Speaking after a party officers' meeting at UUP headquarters in Belfast yesterday, Mr Trimble said he wanted "very much to see things go forward".
The UUP leader announced he was setting up a consultative process with party grassroots members in its 18 constituencies on the direction of the peace process.
The main item on yesterday's agenda was a report by an internal review group which was said to have delivered a downbeat assessment of the state of the peace process, focusing on Ulster Unionist frustration at the lack of progress on decommissioning.
The group said it had earlier in the day met Gen John de Chastelain's decommissioning body, which could not report any progress on paramilitary disarmament.
Before the meeting, anti-agreement Ulster Unionists tried to put pressure on Mr Trimble to toughen his stance on the party's continuing participation in government with Sinn Fein in the absence of IRA disarmament.
The party's honorary secretary, Ms Arlene Foster, said it would not be sufficient to use the meeting as a "stock-taking exercise".
Ms Foster, who is seeking selection as the party's candidate in Fermanagh/South Tyrone in the forthcoming Westminster parliamentary elections, said the ongoing confusion over the leadership's direction could not be allowed to persist.
The DUP deputy leader, Mr Peter Robinson, yesterday dismissed UUP claims that it could regain the South Antrim seat, saying the party was "fooling itself" if it believed it could defeat the Rev McCrea.
Meanwhile, the Alliance Party leader, Mr Sean Neeson, has been defeated in his attempt to become the party's Westminster candidate for East Antrim. Mr Neeson was beaten by a local councillor, Mr John Matthews, in a selection meeting on Thursday night.