The UUP has issued a thinly veiled threat of disciplinary action to MLA Basil McCrea after his call for Sir Reg Empey to step down as leader.
The terse rebuke also said the high-profile Assemblyman was not a senior party member.
It came from Ulster Unionist Party chairman David Campbell, who was an aide to David Trimble during his time as leader.
Sir Reg announced earlier this month that he would vacate the top post before the UUP's conference in the autumn.
His decision came after the UUP-Tory Party pact failed to win any seats at the General Election.
Mr McCrea — viewed as a likely leadership challenger — said Sir Reg's departure should take place “sooner rather than later”.
He also said: “The party really needs to get to grips with issues, about what it stands for, what its vision is.
“The best way of doing that is to have a leadership election.”
In his statement yesterday, issued through the UUP Press office, Mr Campbell said the timetable for the leadership succession had been “overwhelmingly endorsed” by the party executive earlier this month.
He also said that this meeting of the executive had heard “widespread dissatisfaction” being aired over public comments by Mr McCrea.
Mr Campbell continued: “The decisions of the party executive are clear, and they are decisions that Basil McCrea should respect.
“The party will no longer tolerate individual members whose indiscipline threatens the efforts of the wider membership whose primary focus is on the recovery of our party and our country.
“It should also be noted that, while Mr McCrea is an MLA, he cannot be described as a ‘senior' member of the Ulster Unionist Party.
“Mr McCrea has never held a senior post within the UUP Assembly Group, was not voted onto the current Executive by his Constituency Association, and is not a Party Officer.”