Ulster Unionist leader Sir Reg Empey and former DUP man Jim Allister, who resigned from the party in the wake of the deal with Sinn Fein, claimed Mr Paisley had tacitly admitted to being bullied into an agreement.

In a BBC interview, Mr Paisley said the prospect of the so-called Plan B, which would have seen the British and Irish governments share responsibility for governing the Province, had forced him to do the deal with republicans.

He said it was the only option to “save” his country.

However, Sir Reg and Mr Allister said Mr Paisley’s admission smacked of “pushover unionism” – something the DUP leader had in the past accused the UUP of practising.

“The realities of the situation have now dawned on the DUP although for Dr Paisley to admit on the radio that he was ultimately blackmailed and succumbed to that blackmail is an admission that will shock many people,” said Sir Reg.

“Some might say that this sounds like pushover unionism.

“We welcome some of the comments made by Dr Paisley, but perhaps wrongly, we assumed they represented what was in the best interests of the people of Northern Ireland rather than comments given under duress.”

Earlier in the day, Mr Allister also questioned Mr Paisley’s remarks.

“I am intrigued that the primary excuse now for dashing into government with Sinn Fein is the threat of Plan B,” he said.

“If the primary reason for the dash into government with Sinn Fein/IRA was indeed the threat of Plan B, then I am astounded that never once was this so-called Plan B laid before DUP officers, of whom I was one, so that they could make a measured judgment.

“Me thinks he doth protest too much about the supposed threat of Plan B.

“We vilified Trimble for years as the epitome of pushover unionism, now it seems all it took from Blair was the unspecified and exaggerated threat of a supposed Plan B to roll over Ian Paisley.”