Mr Sheridan “divorced” from his former party, the SSP, after a successful libel case against the News of the World over allegations that he cheated on his wife.

The newspaper made further claims after an alleged secret recording.

He will outline the principles of the new party at the city’s Marryat Hall. The rally will also be addressed by trade unionists, anti-war campaigners and MSP Rosemary Byrne. Mr Sheridan’s speech starts at 7.30pm.

Meantime, he has vowed to take on the News of the World over its claim to have video evidence of him confessing to adultery.

The newspaper said the video was recorded by George McNeilage, Mr Sheridan’s best man at his wedding to wife Gail.

It said he taped the conversation on a hidden camcorder but did not release it earlier because he was certain his old friend would lose his court case.

Today Mr Sheridan said, “Yet again the News of the World has printed lies and smears against me.

“They have used a former friend whom I haven’t spoken to for two years to tell lies about me. Mr McNeilage must be seriously hard-up to lower himself to the gutter and co-operate against a former friend.

“A fictitious tape has been invented, concocted and unleashed on a Scottish public sick to the back teeth of the News of the World.

“Their vendetta against me, my family and my political beliefs continues. They are trying to break me politically and personally. They will fail on both counts.

“My new party, Solidarity, grows daily while my relationship with my wife, Gail, is unbreakable.”

But a former political colleague dismissed as “laughable” his claims that the newspaper’s tape was a fake.

The SSP’s Frances Curran said, “I’ve known for months that Tommy was telling lies about this whole affair, and now this tape confirms it in his own words.

“Anyone who knows Tommy and listens to the tape will find his claims that it is a fake frankly laughable. My advice to him is you’re in a hole — stop digging. It is time to tell the truth and apologise to those you have branded liars.”

She claimed the tape vindicated the truthfulness of the 11 SSP witnesses who took the stand during the trial.

The newspaper said the videotape has been assessed by four leading authorities on voice analysis, including American Tom Owen who worked on the verification of Osama Bin Laden tapes for the CIA.