POLICE INVESTIGATING Tommy Sheridan's defamation trial have questioned one of the socialist politician's allies about a plot to destroy court evidence.

Martin McCardie, the actor and playwright, has been quizzed about an attempt to dispose of information on his friend's private life.

He is one of a number of Solidarity members interviewed as part of a perjury probe that is also focusing on whether there was a conspiracy to pervert the course of justice.

The revelation follows last year's court battle involving the News Of The World and ex-Glasgow MSP Sheridan, who sued the tabloid after it alleged he was an adulterer who had cheated on his wife Gail with a former call girl.

The jury at Edinburgh's court of session, after hearing five weeks of salacious claims, found in Sheridan's favour and he was awarded £200,000 in damages. However, the case was marred by contradictory evidence, as 11 of Sheridan's comrades in the Scottish Socialist Party (SSP) claimed he had confessed to visiting a swingers' club.

After the case, Lothian and Borders Police launched an investigation into whether lies had been told in court, an inquiry that has led to many people signing statements that allegedly link Sheridan to a sex club in England.

Officers have now questioned McCardie, who appeared in the films My Name Is Joe and Sweet Sixteen, about a motion he wrote weeks before last year's trial, which called for the destruction of an SSP document that focused on Sheridan's private life.

Written for the Cardonald branch when McCardie and Sheridan were in the SSP, it stated: "This branch demands that any such record or minutes involving comrade Sheridan and his private life, if such a record does indeed exist, should be immediately destroyed."

The motion was circulated from Sheridan's parliamentary email account and eventually seized by News Of The World.

McCardie admitted at the time: "I came up with the motion and took it to the branch."

Detectives are thought to be looking at the possibility of several charges in connection to the case. These include perjury, conspiracy to commit perjury and conspiracy to pervert the course of justice.

Asked about his police interview, McCardie said: "I don't want to talk about that. I'd rather keep that private."

A spokesman for Lothian and Borders Police said: "Inquiries are ongoing."