Stuart Gair, the Scot who spent 17 years waiting to prove he was wrongfully convicted of murder, has died of a heart attack just 15 months after clearing his name.

Mr Gair, 43, suffered the attack on Friday while being filmed by Donal McIntyre, the investigative journalist. He was taken to hospital but died yesterday afternoon.

Last night, friends paid tribute to the man who spent 12 years in prison, wrongfully accused of murder.

Mr Gair was only 25 when, by a majority verdict, a jury convicted him of the brutal murder of 45-year-old Peter Smith during a knife attack in Glasgow city centre.

Mr Smith, a former soldier of West Plean, Stirlingshire, was stabbed in the chest at North Court Lane on April 11, 1989, and died later from his injuries in hospital. Mr Gair denied committing the offence, but was found guilty and sentenced to life imprisonment.

He had put forward a defence of alibi, maintaining that he was in another part of Glasgow at the time of the murder, which occurred near toilets at St Vincent Place.

His fight to clear his name attracted a number of high-profile campaigners. His case was referred back to the Appeal Court by the Scottish Criminal Cases Review in 1999.

In 2000, he was freed on appeal, and began a lengthy series of court hearings.

The question of identification was the key issue at the trial and lawyers acting for Mr Gair argued that, crucially, the Crown had failed to disclose important information to his defence at the time of the trial.

During the trial, a witness, Brian Morrison, who was 19 at the time, identified Mr Gair and his former co-accused as two men he saw come out of the toilets and go in the direction of North Court Lane, a well-known hang-out for homosexuals.

He said he had a good look at the two men and studied their faces carefully. But in previous statements to police, he had given conflicting information.

During an initial statement, he said he would definitely be able to identify the two men he saw and that one of them had threatened him.

But later he told officers: "I have to tell you that a lot of what I have already told the police is not the truth and I made up some of it to attract attention to myself."

Last year when Mr Gair's conviction was overturned he said he was relieved but "shattered".

John McManus, of Miscarriages of Justice Organisation (Mojo), said the stress of being wrongfully locked up had killed Mr Gair. "All we can do now is hope his death will prevent other people having to go through the same circumstances without any support or trauma counselling.

"He was released without any support whatsoever. People have no idea of the level of stress this puts people under.

"Like all of those who have been wrongfully convicted, he was suffering from severe post traumatic stress and he hadn't even received his financial compensation.

"There has to be better support put in place to help people in these circumstances."

Mr McManus said he died at 12.40pm yesterday. It is thought the funeral will be organised by Mojo.