An Ulster Unionist Party member who is trying to oust Mr David Trimble from the leadership urged 13 Assembly members today to back his challenge.
East Derry member Mr David Hoey, who will challenge Mr Trimble at a meeting of the Ulster Unionist Council in Belfast next Saturday, wrote to members of the UUP's Assembly team.
Mr Hoey, who will attend Saturday's meeting as a voting delegate despite not being a member of the ruling council, has sent a letter to MLAs, who failed by two votes to have Mr Trimble's leadership debated at their weekly group meeting at Stormont earlier this month.
Sources close to the Coleraine-based marketing and management consultant revealed he had told the MLAs the Ulster Unionist Council was being given the opportunity this Saturday to "vote for change".
"David Hoey would prefer that there did not have to be a vote this Saturday and that there would be an agreed new leadership by March 27th.
"But with David Trimble showing no signs of standing down, the letter makes it clear that essentially it is up to the council to force change."
Under Ulster Unionist Party rules, the leader must seek the backing of his ruling council every year to stay on. Mr Hoey announced on Friday that he will challenge.
He also confirmed that if he wins Saturday's vote, he would immediately step aside to enable candidates for a new leadership team uniting the party to put their names forward.