Supporters of a postmaster jailed for killing his wife say his conviction is unsafe because it used evidence based on the faulty Horizon computer system.
Robin Garbutt, 57, has been in prison for 12 years but has maintained his innocence since his wife Diana was beaten to death in 2010 in a flat over the post office they ran in Richmondshire, North Yorkshire.
A jury at the time heard Garbutt attacked his wife because he thought she was having an affair and was about to uncover thousands of pounds he had taken from the Post Office.
More than 700 postmasters and postmistresses were wrongly convicted after the IT error made it appear that they were stealing after it duplicated transactions that made it look like money was missing.
Dr Michael Naughton, from Bristol University, said the evidence used to convict him was "no longer reliable".
He told the Daily Telegraph: "The prosecution used the Horizon evidence to support its claim that the motive for the murder was that Robin Garbutt was stealing money from the Post Office side of the business and he needed to kill his wife to cover it up.
"Horizon was used to show he was defrauding the Post Office. I don't know if Robin Garbutt did or did not kill his wife, but I do know that the evidence that led to his conviction is no longer reliable and every aspect has been discredited."
Garbutt told the court he found his wife dead after armed robbers held him up at gunpoint but was given a life sentence.
Since then he has appealed three times to the Criminal Cases ReviewCommission (CCRC) three times for a retrial.
In 2022, the commission concluded "figures from the Horizon system were not essential to his conviction for murder".
The CCRC said: "Much of Mr Garbutt's application to the CCRC focused on the Post Office Horizon scandal, which has led to a number of fraud and theft convictions of former Post Office workers being overturned, many after referral by the CCRC.
"The CCRC decided that this argument could not assist Mr Garbutt, as figures from the Horizon system were not essential to his conviction for murder.
"Other issues concerning scientific evidence were also considered, and the CCRC has now made a final decision not to refer his case for an appeal."
