Mr McGuinness declared that Sinn Fein held that Britain should leave Northern Ireland within a period of up to eight years - a position at complete odds with the Downing Street Declaration, in which the British and Irish governments agreed Ireland could be united only with the consent of a majority in Ulster.
In an interview with Dublin's Sunday Business Post, the Londonderry republican leader stated: 'Anything short of a decision by the British government that they are leaving this country would be unacceptable.'
However, a Sinn Fein source said later that republicans were taking a pragmatic view and had sought to avoid putting time-scales on the peace process.
They would not get 'too bogged down in timetables,' he said. Nonetheless, Mr McGuinness's words will be used as ammunition by sceptics who argue that the republicans are not serious about seeking peace.
Much of the current hope for peace is based on the belief, held by many observers, that Sinn Fein and the IRA are ready to move from the absolutist 'Brits Out' position which for two and a half decades has fuelled the Northern Ireland troubles.
But if Mr McGuinness's statements represent the actual bottom-line position of the republicans then the prospects for peace - which are already in question - will suddenly look much bleaker. The British government - with the full support of Dublin - is clearly not thinking in terms of withdrawal. If Sinn Fein plans to insist on a timetable for British disengagement then the scene is simply set for many more years of violence.
Mr McGuinness - who is regarded by many as the hardline conscience of the republican movement - was at pains to point out that Sinn Fein had yet to give a definitive response to the Downing Street Declaration, saying this could not be expected before the third or fourth week of January. He reiterated recent Sinn Fein demands for the British and Irish governments to clarify aspects of it.
Asked about Mr McGuiness's suggestion that they needed to know more about British intentions, the Prime Minister said he had 'no more to tell' the IRA in the wake of the declaration and added that he did not think Albert Reynolds, the Irish Prime Minister, 'will either'.
Mr Major said in an interview with BBC radio's The World this Weekend: 'I think they should have been able to make the decision very speedily but they haven't been able to. I can be patient for a little while.'
He was emphatic in saying that after 'enormous backing' for the declaration - including 'astonishing' indications of support from within the Republic of Ireland - the republicans would face near-total isolation from the two governments, the churches and both communities in Northern Ireland, and internationally.
Mr Major said that he was not anticipating any further contacts with the provisional IRA in the interim, adding: 'We have set out in the joint declaration which is published what our position is. We are now waiting to hear from them what their response to that is.'
Mr Major, who acknowledged that the republicans were considering the matter and consulting widely, refused to say how long a wait he had in mind. But he repeated that while impatience was understandable after '25 years of violence, of bombs, of bullets, of murders', he thought a 'brief period of patience is worthwhile'.
David Trimble, Ulster Unionist MP for Upper Bann, said Mr McGuinness's words represented the 'traditional uncompromising attitude of the republican movement which thinks it has a right to impose its views on the greater number of people in Northern Ireland'. He said in a BBC radio interview: 'The time has come for the Government to stop temporising with this sort of attitude.'
Sinn Fein's president, Gerry Adams, described Mr Major's comments as 'belligerent semaphore', which was unhelpful and unfortunate. He called again for clarification of the declaration.Reuse content