But the euphoria was muted by the memory of their previous bid for justice five years ago which saw them sent back to prison after only 13 months.
As they emerged from court, the pair walked on to the Royal Mile, calmly raising their fists in defiance as the cheers of their supporters echoed around Parliament Square.
Preparing to go home and hug his young daughter, conceived when he was last on bail, Campbell, now 47, told the crowd: "It’s definitely about time. Everybody knows we are innocent. My daughter will have her daddy home for the first time in nearly five years. Freedom at this time of the year means even more so."
Joseph Steele, 39, simply said: "It’s the best day of my life."
As they addressed the crowd, neither man mentioned his confidence at finally winning their case - they both know the system too well and the scars of their run-ins with justice now clearly run far too deep.
The pair have languished in jail since 1984 and despite repeated hunger strikes, escape attempts and legal challenges claiming they are victims of a miscarriage of justice, their plight behind bars continued.
For more than 17 years Thomas "TC" Campbell and Joe Steele have doggedly denied responsibility for an arson attack which killed six members of the same Glasgow family.
The murders became the focal point for Glasgow’s notorious so-called ice cream wars, a bitterly fought territorial battle for control of the city’s burgeoning drugs trade. The dispute marked one of the most bloody chapters in Glasgow’s violent criminal history.
Ice cream vans had been used for years by Italian immigrants to sell sweets and cigarettes. But in the early Eighties, gangland bosses realised that not only were the vans a good way to launder money, they could also be used for selling and moving stolen goods and, more importantly, drugs.
Strathclyde Police believed that most prominent among the gang bosses was Campbell - one of Glasgow's most feared hardmen, who, as a teenager, had served a ten-year sentence for assault and robbery. In 1984, police believed his gang, the Barlanark Team, had waged a war on the ice cream traders to scare them off routes.
According to the police, Campbell and his henchmen had monopolised ice cream routes across the east end of the city. But in Garthamlock, one van driver Andrew Doyle, 18, had refused to be intimidated.
The teenager had worked for the Marchetti brothers, who had been running ice-cream vans in the city for 20 years. He had told friends that he would never give in to threats or relinquish his route.
On 16 April 1984, Mr Doyle was murdered in an arson attack on his home. Five other members of his family, including his 18-month-old nephew, were also killed in the blaze. The murders stunned Scotland and brought Glasgow’s gangland to the verge of a civil war. The public demanded arrests. Intense pressure was placed on Strathclyde Police and the force was dubbed the "Serious Chimes" squad as they struggled to apprehend the killers.
To the surprise of many, the police arrested six suspects within five weeks.
Under intense security, the case went ahead in October 1984. After a 27-day trial, Campbell and Steele were given life sentences for the murders.
Four others, Thomas Gray, Thomas Lafferty, George Reid and John Campbell, received shorter sentences for assault and attempted murder regarding associated ice cream vendettas, and Campbell was given a further ten years for blasting a van with a shotgun.
They were convicted largely on the evidence of convicted criminal Billy Love.
He gave crucial evidence about allegedly overhearing in a pub Steele and Campbell plotting to kill Mr Doyle. The trial heard evidence from Mr Love and others that both the fire in which Doyle had died and the prior shotgun incident had been intended as "frighteners".
Such was the public outrage at the time that their conviction was welcomed without question, the key was effectively thrown away. But grave concerns quickly emerged about the case and allegations began to surface that the police had framed Campbell.
Rumours also began to emerge that a Glasgow crime boss, Thomas McGraw, known as "the Licensee", had "fitted up" Campbell and Steele to move in on their burgeoning business.
In the early Eighties the Licensee had earned his nickname partly because he was the owner of Glasgow’s notorious Caravel Bar but mainly because his enemies believed Strathclyde Police had effectively given him a licence to operate.
Following the conviction, the Licensee went on to become one of the most feared gangsters in Glasgow, taking control of the ice cream vans, taxi firms and burgeoning heroin trade.
To the surprise of few at the time, Campbell and Steele’s first appeal was thrown out by the courts in 1985. After this Campbell went on high-profile hunger strikes.
Steele’s response was to embark on a series of escape bids. One break-out saw him escape to London, where he glued himself to the gates of Buckingham Palace to attract attention to his plight.
In 1996, as their desperate bids for freedom continued to fail, they adopted more conventional methods of seeking justice after the key prosecution witness in the case, Mr Love, admitted perjury claiming his evidence had been lies.
Shortly after Mr Love’s admission, Campbell and Steele were released on bail pending their appeal, based largely on the key witness’s retraction.
During his release Campbell witnessed the birth of his daughter, Shannon.
But the case was rejected after a vote by appeal judges narrowly went against them. The 2-1 decision meant they were returned to their cells.
The pair then tried to appeal that decision to parliament through the offices of the Scottish Secretary. But Donald Dewar sided with the judges and they remained in prison. In September 1998, Steele’s wife gave birth to a baby daughter, conceived while he was at liberty, but the news remained overshadowed by his plight behind bars.
Since their return to prison, the pairs’ lawyers turned to the newly-established Scottish Criminal Cases Review Commission set up to probe miscarriages of justice.
But they were to wait another two years for the Commission finally to refer the case back to the Appeal Court and at last set them back on yesterday’s new road to freedom. The appeal will be heard in the New Year.
Their fightback against the system may yet come back to haunt Strathclyde Police and beg the real question: if they didn’t do it, who actually committed the murders?