The family of Derek Bentley yesterday called for a public inquiry after the teenager's conviction for murdering a policeman was finally quashed 45 years after he was hanged.
Jubilant relatives and campaigners said justice had at last been done after the Court of Appeal in London ruled the conviction of the "simple-minded" teenager was "unsafe".
The Lord Chief Justice, Lord Bingham, launched an unprecedented attack on the trial judge in the case, the late Lord Chief Justice Goddard, accusing him of denying 19-year-old Bentley the basic right of a fair trial.
Lord Bingham, sitting with Lord Justice Kennedy and Mr Justice Collins, commented: "It must be a matter of profound and continuing regret that this mistrial occurred and that the defects we have found were not recognised at the time."
Bentley's niece, Ms Maria Dingwall-Bentley (35), from south-west London, emerged from the court delighted and said: "My family has waited 45 years for this. Today is a great victory for British justice."
Holding a copy of the court's 52-page written judgment above her head on the steps of the Law Courts, she said: "I am absolutely bowled over the moon."
But the day was also "tinged with great sadness" because neither her mother Iris - the hanged man's sister - nor Bentley himself could witness the day's events, she said.
"We definitely want a public inquiry now," she added.
Ms Dingwall-Bentley took over the lifelong campaign to clear Bentley's name mounted by her mother after he was executed at Wandsworth Prison in January 1953.
In 1993, Mrs Iris Bentley won a partial victory when the then Home Secretary, Mr Michael Howard, granted a limited posthumous pardon, accepting that her brother should not have been hanged.
She died of cancer before it was announced in November last year that the Criminal Cases Review Commission was sending the case back for the judges to reconsider.
Later, at a press conference, Ms Dingwall-Bentley opened a bottle of 1958 Moet & Chandon champagne which her grandfather, Derek's father, had bought in anticipation of this day.
Later, campaigners and friends paid homage at Bentley's grave. Flowers were placed on the site at Croydon Cemetery, south London, where he lies next to his sister.
Bentley was convicted of murdering PC Sidney Miles during a break-in at a Croydon confectionary warehouse in 1952. The teenager, who had a mental age of 11, played no physical part in the murder. He was convicted primarily on the basis of police evidence that he used the words "Let him have it, Chris" to his 16-year-old accomplice Christopher Craig before Craig fatally shot PC Miles.
After yesterday's decision Craig (61), who was detained at Her Majesty's Pleasure after their trial and served 10 years in jail, issued a statement in which he said he was "grateful and relieved", but saddened that it had taken so long for the authorities to "admit the truth".
"I am truly sorry that my actions on November 2nd, 1952, caused so much pain and misery for the family of PC Miles, who died that night doing his duty," he said. Craig said he would "never, ever" give any further press interviews about the case.