The report claimed that the document would bring the prospect of a united Ireland closer than at any time since partition in 1920.
Sir Patrick Mayhew, the Northern Ireland Secretary, is under mounting pressure to allay Unionist fears and is expected to make astatement in the Commons today.
The report said a proposed new "joint north-south Irish authority with radical executive powers" would make European policy for the whole island and quoted the document as stating that "the British Government has no limits to impose on the nature and extent of functions in the executive field".
The leak will increase Unionist unease that the framework document, in which the two governments will sketch their vision of new political arrangements in Ireland, will contain proposals unacceptable to Unionists.
Downing Street said the document was not complete and there was no question of agreeing to joint authority by London and Dublin. It said the outcome would be put to the people of Northern Ireland in a referendum. Whitehall sources accepted the draft was probably authentic but did not know at what stage of the talks it had been written. Parts could have been overtaken by new drafting. Observers in Belfast said last night the report could only represent a partial picture of the framework document since both governments knew a new framework must not alienate either Unionists or nationalists.
Last night David Trimble, Ulster Unionist MP for Upper Bann, said: "The Government knows our position. We have refused to accept any question of joint authority or any slippery slope leading thereto. If John Major lets us down, he cannot expect support."
Unionist MPs are frustrated they were not shown a document in advance of publication and say requests to the Prime Minister for "consultation" over its form were rejected.
Meanwhile, the Irish government is pressing for the early release of IRA prisoners in British jails amid fears that Britain could free on licence Lee Clegg, the paratrooper imprisoned for life for killing a joyrider. The Irish government postponed a further release of republican prisoners yesterday but the cabinet is expected to go ahead as planned shortly.
One Irish government source said: "We would like to see all individuals given equal treatment under the law. It is very important to see the confidence of the republican community in the North in the administration of justice is not undermined."
There is anxiety in Dublin at the failure of the talks between British Government officials and Sinn Fein leaders. British ministers are demanding the decomissioning of IRA weapons, while Sinn Fein seeks the release of IRA prisoners.Reuse content