Paddy Nicholls was released on bail following the presentation of new evidence rubbishing the original pathologists' conclusions that the "victim", Gladys Heath, had been beaten and suffocated.
Mr Nicholls, a stroke victim who suffers from arthritis, will become the worst victim of a miscarriage of justice to be released if the Court of Appeal accepts the new evidence, possibly in April. Previously, Judith Ward had served the longest term - 18 years - for an IRA bombing she did not commit. The Birmingham Six served 17 years.
Mr Nicholls was convicted of the murder of Mrs Heath, a 74-year-old family friend, whom he found slumped on the floor of her home in 1975. He always maintained that he found her in that condition, but two pathologists concluded that she had died of a heart attack after being suffocated and severely beaten about the face.
However, a review of the evidence by Professor John Crane, an Irish state pathologist, concludes that the facial injuries were "trivial" and were probably caused in a fall after the heart attack. In a report to the Criminal Cases Review Commission, obtained by the Independent on Sunday, he describes the earlier findings as "meaningless ... ambiguous ... inadequate, inappropriate and misleading".
Full report, page 4