Rosemary Byrne, a former fellow MSP, told a jury that far from admitting he had visited a sex club, as alleged by others who attended the meeting, Sheridan denied it. Anyone who gave a different account was "not telling the truth," added Mrs Byrne.
"It was like a kangaroo court...one of the things I found out was a group had met before the meeting and had already found him guilty and were determined, no matter what he said, that he was guilty," she stated.
Mrs Byrne, 62, a retired teacher, also alleged that certain people within the Scottish Socialist Party had been "out to get" Sheridan and had been prepared to do whatever it took to have him ousted as the party leader.
Sheridan, 46, and his wife, Gail, 46, deny committing perjury during his successful defamation action against the News of the World in 2006.
Several SSP members who attended a special meeting on 9 November, 2004, have testified to the High Court in Glasgow that Sheridan admitted he was an unnamed MSP in a News of the World article the previous weekend about a visit to Cupids, a swingers' club in Manchester.
The trial continues.