The deputy leader strongly denied claims that pressure was applied to the First Minister to stand down.

This was even though reliable sources told the News Letter that DUP MLAs had signed a petition which called for Mr Paisley to reveal a date on which he would go.

The paper was never presented to him, because he decided himself that he would go.

But it was claimed that had he not stepped down, there was a plan to call a DUP Party Officers' meeting on Saturday with a view to forcing a leadership election.

It is said that 33 of the 36 MLAs signed the paper.

Mr Robinson responded: "Such a document does not exist."

He continued: "Let's be clear, you are going to hear all sorts of stories over the next number of days and they have a twofold purpose, to try and diminish Ian Paisley's standing so that somehow he is forced to leave the political stage; and the other purpose is to try to suggest to the party's supporters in the country that there was some kind of night of the long knives, that there is things they should be suspicious about and they should lose some kind of confidence in the party.

"Those kind of tactics are not going to work."

Senior DUP members, including Jeffrey Donaldson, Nigel Dodds, Gregory Campbell and Edwin Poots all gave interviews denying the leader was the victim of any coup and repudiating suggestions of him being put under any pressure.

Mr Poots said: "I never saw any letter; never signed any letter and I am absolutely sure there was never a letter handed to Dr Paisley at any stage."

Opponents suggested there was a difference between a letter and a petition.

They claimed - though Mr Paisley went of his own accord - that the DUP leader jumped with a push.

UUP leader Sir Reg Empey said: "This departure has been more brutal than that which was given to Margaret Thatcher in 1990.

"It was orchestrated, meticulously prepared and executed. It was a political coup."

Former Paisley adversary and ex-SDLP deputy leader Seamus Mallon added: "He very obviously was forced out by his own political party. He was destroyed by his own political party.

"It's a paradox in itself that Ian Paisley, who declared so many leaders of unionism should go - Terence O'Neill, Faulkner, Chichester-Clark, David Trimble - has become the one that his own party (the party he nurtured) decided must go."

Mr Robinson said: "There are people with a vested interest and some of them are attempting to tarnish Ian Paisley's legacy.

"They believe that all political careers should end in failure but Ian Paisley's career has been a massive success.

"He has brought the DUP from being a small ginger group protest organisation to being a major political party and the party of government."

He concluded: "The reality for all of us in politics is that there are people who want to stir difficulties up. Ian Paisley is, as well as being respected within the party, is loved within the party."

The DUP deputy, however, revealed that he had had conversations with Mr Paisley about when he would quit.

He added: "The timetable I indicated to Ian, when he told me he was considering this course, was a timetable much longer than the one he has chosen.

"Ian Paisley has taken his decision," he insisted, "and anybody who suggests it's anything other than that, I think doesn't know Ian Paisley."

The claim is that MLAs acted, amid what they saw as Mr Paisley's lack of movement on addressing his future, but the suddenness of the move may have been as a result of anger at the leader's appointment of Mr Paisley Jr to the Policing Board - just days after he quit as junior minister.

Pressure had been building for the DUP leader to step aside, after Paisley Jr's resignation, because of the negative impact of the Chuckle Brothers image, the Dromore by-election result and his age.

Mr Paisley, in the end, took the decision to go himself, but discussions between him and senior party members took place throughout Monday and on Tuesday morning.