Witness recalls shock at seeing Tommy Sheridan in her living room

Elizabeth Quinn was once the next-door neighbour, and a "good friend", of former News of the World columnist Anvar Khan, who has previously told the trial at the High Court in Glasgow that she had a string of casual sexual encounters with Sheridan.

They included a visit to a swingers' club in Manchester and liaisons at Sheridan's home, Ms Khan's flat and Ms Quinn's flat, the court was told.

Ms Khan told the jury that she had engaged in some sexual activity with Sheridan while she was staying in Ms Quinn's flat in Glasgow, but stopped short of "full sex".

The politician is on trial accused of lying under oath during his successful defamation action against the News of the World in 2006.

Sheridan denies lying to the courts during the action, which followed the newspaper's claims that he was an adulterer who visited swingers' clubs.

He and his wife Gail, both 46 and from Glasgow, are accused of lying under oath.

Mr Sheridan won 200,000 in damages after the newspaper printed the allegations.

But Ms Quinn, 70, a retired headteacher, told the trial today that she arrived home on August 11 2003 to make preparations for a painter to come the next day.

She said: "Anvar had come to stay for a couple of days.

"It was the afternoon, maybe about three-ish. Anvar Khan came into the living room - there's only one room she could have come from, the room she was staying in.

"Then Mr Sheridan came into the living room. I was so stunned by the fact of him coming into my living room and presenting himself to me. I thought it was very stupid behaviour."

She also told the court she had "gained the impression" that Ms Khan and Sheridan had had sex, adding that Ms Khan "had led me to believe that that was what had been going on in the bedroom".

She also told the trial that Ms Khan had spoken to her about a visit to Cupid's sex club, adding that she had told her it was "boring", telling the court: "I didn't get the impression she would be repeating the experience."

Ms Quinn said she reported the incident to the police following Sheridan's successful action against the News of the World, saying she had "feelings of disquiet" about the outcome of the case.

Under cross-examination from Sheridan, she said: "I felt there was something amiss about the outcome of the trial.

"I was reading in the papers that there was an investigation following the original trial, and I thought maybe I had something salient to pass on," she told him.

The trial, before Lord Bracadale, continues.