William Mills speaks quietly and seems unexpectedly sombre for a man who has just won his freedom. Last week his conviction and nine-year sentence for armed robbery was quashed by three judges who raised serious questions about the way he was identified.

One might expect him to be ebullient - euphoric, even - when we meet on a sunny afternoon in Partick, but his relatives explain that the experience of mistaken identity that saw him serving 12 months in prison has left the man who was once "the life and soul of the party", somewhat withdrawn.

Rather than celebrating with a big party at the weekend, he said he just wanted to savour some family time with Toni Stringfellow, his partner of 20 years, and their two teenage daughters.

The main evidence against Mr Mills came from two police officers who identified him from CCTV images of a masked man carrying out the armed robbery. More than £8000 was stolen in the raid on the Royal Bank of Scotland in Dumbarton Road on May 24, 2007.

Mr Mills, 42, had met both officers in the months running up to his arrest in completely different circumstances and fears that his partner's tendency to be a Good Samaritan could be the only link between him and a robbery he did not commit.

Ms Stringfellow, his partner of the past 20 years, is known in the area for her kindness and charity work. Some months previously she had helped a girl whose face had been slashed and taken her home to clean her up.

A trail of blood brought a police officer to the door - the same police officer who identified Mills from CCTV in the bank.

"I just took her in to give her a cup of tea and see if she was OK," says Ms Stringfellow. "When the police came she asked Billy to say she wasn't there. They said they'd seen the trail of blood and would hammer the door down unless he let them in.

"She didn't want to talk to them about what happened. It was between her and the police and had nothing to do with us."

Mr Mills says he'd met the other police officer who identified him after forgetting to renew his car insurance on time.

At the original trial, Mr Mills blamed another man but failed to convince the jury. Last week, the appeal court was told new DNA evidence had linked that same man to the crime.

Lord Gill, the Lord Justice-Clerk, sitting with Lords Eassie and Philip, concluded that Mr Mills had been the victim of a miscarriage of justice.

"This was a prosecution that stood or fell by eye-witness identification alone. That is a form of proof that has been shown to be, in some cases, a dangerous basis for a prosecution, as history shows," said Lord Gill.

"It is a matter of concern that an important part of the case for the prosecution was the evidence of two police officers, neither eye-witnesses, who made positive statements that Mills was the robber on the basis of looking at CCTV stills. The new evidence confirms all our reservations about this conviction."

The case is finished but the questions remain.

It was 5.30am on June 7, 2007 when Mr Mills first heard the police dogs barking outside his tenement flat - the first in a long line of bizarre events that led to him being wrongly imprisoned for 12 months.

"You don't expect anyone to come to your door at that time in the morning and I just couldn't understand it," he says quietly.

"They grabbed me and threw me to the floor with my boxer shorts on. I remember thinking What the hell is going on? Why are they pointing guns at me and my family?' I thought they must be kidding on to start with. I thought it was because I'd forgotten to renew my car insurance."

It was only once Mr Mills got to the police station that he was asked about and charged with an armed robbery on the Royal Bank of Scotland.

All the evidence seemed to be stacked in his favour. At the trial the bank tellers described the masked man as having a South African or Eastern European accent. Mr Mills, who was born and lived most of his life in Partick, has a soft Glaswegian accent.

Forensic tests ordered by the defence indicated that the man in question was between 5'9'' and three quarters and 5'10'' and a half. Mr Mills is 6'1''. And most crucially, a door stop used by the robber to wedge open the bank's door contained DNA that did not match that of Mr Mills.

"When the expert came to Barlinnie to measure me she said she could eliminate me as I'm 6ft1'," he explains. "I was allowed out on bail and no-one even seemed to think it would go to trial."

The following August - ten months after being released - he was told that the trial would go ahead.

"I was sentenced to nine years," he explains. "I just couldn't believe it. I don't know how they came to a guilty verdict. Even the prosecutor said he wasn't in the habit of prosecuting innocent men."

Mr Mills says the DNA report wasn't even included in the original list of evidence. On the 8th day of the 10-day trial the defence called a halt to proceedings because the doorstop was missing. It was only then that Mr Mills learnt of a DNA report stating that he did not match the DNA found on the doorstop.

While on remand in Barlinnie another inmate suggested that he should speak to Michael Absalom, 38, a South African, who had been jailed for eight-and-a-half years for armed raids in Glasgow and Troon, Ayrshire, around the time of the Dumbarton Road raid.

It was only at the prompting of Mr Mills and his lawyer that the DNA sample from the doorstop was checked against that of Absalom in February this year. It tested positive. In fact, there was a 540 million to one chance of it coming from someone else.

Liam O'Donnell, Mr Mills' solicitor, says he will be claiming for compensation but he says that will not make up for what he has lost.

"It was so hard not being able to see Toni and the kids," says Mr Mills. "I'd never spent Christmas or birthdays away from them. If the DNA test hadn't been done I would have just been sitting there for years." On the DNA trail DNA fingerprinting or DNA typing (profiling) as it is now known, was first described in 1985 by an English geneticist named Alec Jeffreys. Dr Jeffreys found that certain regions of DNA contained DNA sequences that were repeated over and over again next to each other DNA evidence was first used in a British criminal investigation in 1986 during the trial of Colin Pitchfork, later jailed for life for the murder of 15-yearold schoolgirls Lynda Mann and Dawn Ashworth in Leicestershire.

Richard Buckland, 17, had been charged with one of the murders but cleared thanks to the development of DNA evidence. Former US death-row prisoner Kirk Bloodsworth was sentenced to death for the rape and murder of a nine-year-old girl in 1984 and campaigned for DNA testing to be used in his case.

After eight years in jail his was the first capital conviction in the US to be cleared using DNA . OJ Simpson, the American actor was acquitted in 1995 of the murder of ex-wife Nicole Brown Simpson, 35, and her friend, Ronald Goldman, 25, despite DNA evidence identifying him at the scene of the crime. The defence questioned methods and procedures. Michael Shirley from Leamington Spa, Warwickshire, was freed in July 2003, after spending 16 years behind bars for the brutal murder of Portsmouth barmaid Linda Cook after DNA tests showed he was not the killer. The Police Service of Northern Ireland suspended the use of low copy number DNA analysis, which can establish a profile from just a few cells, after the acquittal of Sean Hoey, the man accused of the 1998 Omagh bombing in 2007. Mr Justice Weir called into question the use of DNA analysis which produces results from minute amounts of DNA.