The Post Office has asked judges to rely on 30-year-old newspaper reports in its bid to stop a sub-postmaster’s conviction being overturned because it cannot find its own evidence, The i Paper can reveal.

Steve Marston, 72, was convicted of theft and false accounting offences in 1998, after suffering accounting problems following his use of Capture, a primitive and faulty piece of software that predates the Horizon system.

His case, alongside that of sub-postmistress Patricia Owen, is now being considered by the Court of Appeal following a referral from the Criminal Cases Review Commission, the miscarriages of justice watchdog, with a full hearing later this year.

The Post Office is attempting to block Mr Marston’s conviction from being overturned – but is unable to produce the original evidence it used to prosecute him.

A spokesperson told The i Paper the Post Office believes it has an “obligation” to respond to Mr Marston’s appeal, and any others, on a “legal and factual basis”.