Former Scottish Socialist Party leader Tommy Sheridan has broken down in tears in court while denying that he had cheated on his wife.
Tommy Sheridan said he would never betray wife Gail
In a statement, following four hours of questioning in his defamation case, Mr Sheridan said the News of the World's evidence was a "complete fabrication".
"I would call it the mother of all stitch-ups" he said.
He began sobbing while talking about the sex allegations and the trust he had received from his wife.
Mr Sheridan had begun to choke with emotion as he explained his reasons for pursuing the legal action.
Addressing the jury at the Court of Session in Edinburgh, he said: "I have got to say to you ladies and gentlemen I am either a complete and utter idiot or I am someone who loves his wife deeply and would never betray her trust."
After saying that his wife had trusted him for many years, before and after they were married, Mr Sheridan began to sob.
He then apologised and said: "Of all the things about me the worst thing said was that I had sex on my wife's bed with another woman behind my wife's back. I find that unacceptable."
After a long pause Mr Sheridan, who had made a reference to Superman, said he was not made of steel but flesh and blood and although the allegations had hurt him they would never destroy him.
Earlier, the Glasgow MSP said allegations that he attended a swingers club were fabricated in a battle for the "heart and soul" of the party.
Mr Sheridan, who is representing himself in a £200,000 action against the News Of The World, was questioned by Michael Jones QC, who is acting for the paper.
Mr Sheridan denied he had been forced to step down as leader of the party.
He told the court he had agreed to vacate the position after a discussion with the party's ruling executive.
The court was shown video footage of interviews given by the MSP which showed him saying he wanted to spend more time with his family.
"Did you dismiss as nonsense claims that you were forced out by your party?" Mr Jones asked.
Mr Sheridan, 42, said: "Absolutely. I agreed to step down after the executive committee discussed with me how I needed to deal with what we expected to be serious allegations about my private life."
Mr Jones asked: "You weren't forced out?"
Mr Sheridan, from Cardonald, Glasgow, said: "I'm telling you I was not forced out."
Mr Jones later focused on what he described as Mr Sheridan's "strategy of denial" during the court case.
The QC was referring to allegations made on Thursday by senior SSP officials that Mr Sheridan admitted during a party meeting he had visited a swingers club.
This accusation was dismissed as nonsense by Mr Sheridan.
Mr Jones said: "So far the people who have lied in this case are members of the Scottish Socialist Party."
Mr Sheridan responded by saying: "That's correct because there's a political battle for the heart and soul of the SSP.
"I know you don't care about that. I care about it because it is a party I have fought hard and long to build.
"This courtroom has become an arena for that battle."
Mr Sheridan denied having a pub meeting with Colin Fox
He agreed with Mr Jones that he himself would tell lies for political reasons.
"I think, sometimes, when you are dealing with the power of the law and the most reactionary scab outfit in the world you will have to fight dirty, yes," he said.
Mr Sheridan claimed he was being "set up".
Mr Jones moved on to the matter of a contentious SSP minute that resulted from a meeting in November 2004.
The meeting resulted in Mr Sheridan stepping down as party leader.
Mr Sheridan denied meeting party leader Colin Fox and national secretary Allan Green in a pub on 12 May and being given the minute to read.
"That's a lie," he said. "I'm telling you that I have never seen the minute."
Mr Sheridan earlier told the court he had decided to "take on the News of the World for telling a pack of lies".
He said the decision to bring the £200,000 civil action had been the reason for stepping down as leader of the SSP.
He said he did not want the party he had helped build to get dragged into the costly case when they were facing a financial crisis.
Mr Sheridan rounded on Mr Jones when the lawyer accused his wife Gail of "just hanging around".
"When you are talking about a woman of considerable substance don't talk about her hanging round all day," he said.
When Mr Jones asked what Gail Sheridan did, the MSP told him: "Sometimes, unfortunately, she shops."
He said she also had business to attend to and added: "Sometimes, unfortunately, she cries. She cries a lot because of the lies that are published in newspapers as a result of your case."
Mr Sheridan said the rumours about him attending Cupids sex club in Manchester had been circulating since 1996 and said it was "ridiculous" to think he would do such a thing.
The case continues.