Ulster Unionist leader Mr David Trimble has appointed rival Mr Jeffrey Donaldson to his talks team, sources in the party confirmed tonight.
Members of UUP executive were told at a meeting in Belfast today that Mr Donaldson would take part in the negotiating team next week at Downing Street. The move is seen as an attempt to save off a leadership challenge from anti-Good Friday Agreement elements in the party.
Sources said the Lagan Valley MP, who had been touted as a possible leadership challenger, will join UUP leader Mr David Trimble and Stormont minister Mr Michael McGimpsey at crucial peace process talks involving Prime Minister Tony Blair, the Taoiseach Mr Ahern, the nationalist SDLP and Sinn Fein.
The talks will aim to resolve differences over IRA disarmament, policing, the scaling down of Army bases and personnel and sanctions against Sinn Fein.
It is understood Mr Donaldson accepted.
But Mr Donaldson would not comment today on speculation about him launching a leadership bid.
Some supporters would like to see the Lagan Valley MP team up with Sir Reg Empey as his deputy, with Mr Donaldson leading the party at Westminster and the Stormont Enterprise Minister taking charge at the Assembly.
But in a statement issued as the UUP Executive was meeting, Sir Reg said he had no intention of challenging Mr Trimble.
"The last thing the Ulster Unionist Party needs at this critical stage in the political process is for it to become the focus of all media attention," he said.
"The Republican movement is to blame for the present political instability. Its failure to put its weaponry beyond use is undermining unionist support for the Belfast Agreement.
"The objective for all unionists in the coming weeks is to maximise pressure on Sinn Fein/IRA to force them to honour the promises they have made. The Ulster Unionist Party must hold its nerve and prepare to square up to its real opponents in the coming weeks."