Police have charged a close ally of Tommy Sheridan with perjury, it was confirmed today.

Rosemary Byrne, 59, was arrested and charged on Tuesday by officers from Lothian and Borders Police investigating allegations of perjury during Mr Sheridan’s libel trial against the News of the World in 2006.

The move comes after Mr Sheridan himself was charged with perjury just days before Christmas.

Ms Byrne, from Irvine, Ayrshire, was elected to the Scottish Parliament in 2003 as a member of the Scottish Socialist Party (SSP) but lost her seat last year after she and Mr Sheridan left to form a new party called Solidarity.

She gave evidence on behalf of Mr Sheridan during his trial against the Sunday newspaper, which had accused the former SSP leader of being a “swinger” and attending orgies.

The paper was ordered to pay £200,000 in damages to Mr Sheridan after a jury found that he had been libelled by the stories.

A spokeswoman for Lothian and Borders Police said today: “We are confirming that a 59-year-old woman has been charged and released in connection with an ongoing investigation. A report will be sent to the procurator fiscal and inquiries continue in respect of others.”

Although the spokeswoman declined to say what the woman had been charged with, Ms Byrne’s colleagues confirmed that she had been charged with perjury following her arrest on Tuesday.

Jim Monaghan, a spokesman for Solidarity, said that Ms Byrne had cooperated fully with detectives and had gone voluntarily to a police station in Edinburgh. She was later charged, he said.

He added: "We consider this to be nothing more than a political witch-hunt. I don’t think we have anything to worry about. We believe it’s just police intimidation and it’s to put pressure on members of Solidarity and to put pressure on Tommy Sheridan. We expected this as part of an ongoing pressure campaign. Our members have done nothing wrong and have nothing to fear in a court at all.”

Mr Sheridan, the permatanned socialist firebrand renowned for his rousing speeches and protests, was charged with perjury in December just minutes after finishing his Sunday morning phone-in show for an Edinburgh radio station.

Plain-clothes officers arrested him after screeching into the Talk 107FM car park and blocking his path as he was preparing to leave. At the same time, officers searched his house in Glasgow where his wife Gail was also detained.

Mr Sheridan described the decision to charge him as “farcical” and said that he was the victim of a “political witch hunt”. In a statement at the time, he added: “It’s nine days before Christmas. My house has been ransacked, my wife has been traumatised, and my two-and-a-half-year-old child has been reduced to tears by the presence of nine police officers.”

There was also mounting speculation today that Mrs Sheridan, whose testimony on behalf of her husband electrified the Court of Session in Edinburgh, may also be charged.

Reports said that Mrs Sheridan and her father, Gus Healy, 70, who also testified for Mr Sheridan, were expected to report to an Edinburgh police station next Tuesday.

The charges come more than a year after detectives launched an investigation into allegations of perjury during the libel trial. Lothian and Borders Police was ordered to begin an inquiry after the trial judge raised concerns about “contradictory evidence” given during the case.

During the trial, at which Mr Sheridan represented himself after sacking his legal team, five members of the SSP gave evidence that Mr Sheridan had admitted visiting a swingers' club in Manchester - an accusation he strongly denied. Ms Byrne endorsed his denial, telling the court that no such admission had been made.

The trial gripped Scotland and made the Sheridans arguably the country’s most glamorous political couple.

Appearing in the witness box, Mrs Sheridan told the jury that she would have murdered her husband and dumped his body in the River Clyde had he been unfaithful to her.

The jury of six men and five women dismissed the News of the World’s claims that the socialist MSP was a serial adulterer and a swinger who habitually cheated on his wife and participated in orgies. The News of the World, whose parent company, News International, owns The Times, described the verdict as “perverse” and is appealing.

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