The wife of former Scottish MP Tommy Sheridan has been charged with perjury over allegations that she lied to jurors during a high-profile libel trial about his sex life, police sources said on Wednesday.

After Gail Sheridan, 44, was charged and released following several hours of questioning in Edinburgh, the former leader of the Scottish Socialist Party branded the police investigation a vendetta and vowed to clear his family's name.

His father-in-law Angus Healy, 71, was also charged with perjury almost 18 months after Sheridan successfully fought a libel action against the News of the World tabloid.

Sheridan is already facing perjury allegations after he was charged in December.

They face up to five years in jail if convicted.

In August 2006, a jury found the 43-year-old had been defamed by the newspaper and he was awarded 200,000 pounds.

He had denied claims he had cheated on his wife, indulged in drug-fuelled orgies and had visited a "swingers" sex club.

His wife, a former air stewardess gave evidence on his behalf -- contradicting other witnesses -- and dismissed the claims as rubbish.

Police were asked to launch an investigation by the trial judge after he raised concerns of "contradictory evidence".

In a statement issued on Wednesday, a spokesman for Borders and Lothian police said: "A 44-year-old woman has been charged and released in connection with an ongoing ... police investigation.

"A report will be sent to the Procurator Fiscal and inquiries are continuing in relation to others."

He also said a 71-year-old man had been charged in relation to the same investigation but declined to elaborate.

Police sources confirmed to Reuters the pair's identity and the nature of the charges.

Speaking to waiting reporters outside Edinburgh's Gayfield police station late on Tuesday, Sheridan branded the police investigation a vendetta.

"I am dismayed, disenchanted and disgusted by the behaviour of Lothian and Borders Police," he said.

"The streets of Lothian must be crime-free if the police can devote time to harassing a family."

Gail Sheridan and her father declined to comment.