The Rev Ian Paisley tonight challenged British Prime Minister Mr Tony Blair to give details of any secret deal he may have struck with Ulster Unionist leader Mr David Trimble.
As the British and Irish governments prepare for a new round of negotiations in London later this month, the Democratic Unionist chief urged the Prime Minister to disclose any arrangements agreed during last year's failed bid to restore devolution in Northern Ireland.
Mr Paisley said he had written to Mr Blair demanding details of his dealings during the process which collapsed amid uncertainty over IRA disarmament.
Mr Trimble backed out of plans to restore the power-sharing Executive in Belfast after General John de Chastelain's decommissioning body refused to give precise details on what weapons the Provisionals had destroyed.
"The public are entitled to know the detail of the Trimble October 2003 deal," insisted Mr Paisley.
"If we are going to move forward in these negotiations we must be made aware of the precise nature of the agreement Mr Trimble put on hold and whether any elements of it are binding in present circumstances."
The hard-line unionist issued his appeal as it emerged fresh talks on Northern Ireland's future are expected to be held in London's Lancaster House later this month.
The two Governments are to call the political parties in Belfast together for an intensive three-day negotiating session to try to restore devolution in advance of the European elections in June.
Prime Minister Tony Blair and Taoiseach Mr Ahern are prepared to clear their diaries to facilitate the process.
London and Dublin fear they need to inject major momentum into the process to prevent it drifting without resolution towards the summer.