Demands for changes to ‘barmy’ rules on digital evidence have government’s ear

Jones was initially made aware of the issue after barrister Paul Marshall wrote to him detailing the issue.

“It is wrong that the law says the computer is always right unless the defence can prove otherwise. The [subpostmaster] defendants really had no power to be able to prove that when they were being prosecuted,” said Jones. “It is clear now that this is one of the biggest miscarriages of justice in British legal history.”

He said that, beyond the rule itself, there are questions about the ability of courts to understand computer-based evidence. “It is also about the competence and capacity of the courts to deal with this type of evidence,” he added. “You would hope, following a miscarriage of justice of this scale, that there will be momentum to try to resolve all these issues.”

Marshall, a barrister at Cornerstone Barristers, has worked on the cases of subpostmasters sent to prison based on flawed evidence, who will hear later this month whether the Court of Appeal will quash their convictions.

He said, among the many failures identified in the Horizon scandal, the failures of the court system are not prominent, but should be.

“While it is a scandal in respect of the sheer mendacity of the Post Office as a public institution, and catastrophic failures in its governance and corporate leadership, it is also a scandal in the scale of the systemic failure of the court system,” said Marshall. 

“Future generations are likely to look askance at English law’s – and English courts’ – apparent inability to engage satisfactorily with digital evidence, an inability that the Post Office scandal has all too painfully exposed.”

He added that if judges are unable to identify whether a trial is fair or not, the whole court system is undermined. “Were courts an airline that failed so frequently, it would be grounded and no one would fly. But there is no choice it’s the only system available,” he said.

Referring to the Post Office Horizon scandal, Marshall said: “That the courts routinely accepted the Post Office’s evidence, suggests that the courts failed in their purpose to effectively test and weigh the relevant evidence. 

“The courts plainly did not do so because the evidence of widespread failure of the Horizon system was not before the court. The reason for this is largely to do with inadequacies in the law concerned with the reliability of computer-generated evidence that took a wrong turn in changes made on recommendation by the Law Commission.

“That the consequence of failure is that large numbers of people were imprisoned and their and their families lives and livelihoods wrecked ought to be a matter of serious public concern.”

Marshall criticised the current government inquiry into the Post Office scandal, chaired by former judge Wyn Williams, which he said will not investigate court failures.

“The inquiry terms of reference do not extend to these critical issues. The reason is almost certainly that, were the question to be answered candidly, it would be the occasion for institutional embarrassment and further erode public confidence in the criminal justice system. 

“Both the courts and the government, for different reasons, have an interest in the hard questions remaining unaddressed and unanswered,” he said.

Marshall added that it is insufficient to blame the Post Office for having abused the processes of the courts when the court itself “should be effective in preventing its process from abuse on this scale”.

Both the courts and the government, for different reasons, have an interest in the hard questions remaining unaddressed and unanswered