Government calls for expert views on computer evidence to learn lesson from Post Office scandal

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The government is calling for evidence from experts in computing and law to help it ensure no repeat of the miscarriages of justice in the Post Office scandal

By

Karl Flinders,
Chief reporter and senior editor EMEA

Published: 21 Jan 2025 0:01

The Department of Justice has issued a call for evidence as it examines the role of computer evidence in the criminal justice system to prevent another Post Office scandal.

Computer evidence was used to wrongly convict hundreds of former subpostmasters and their staff, based on evidence from the error-prone Horizon computer system from Fujitsu used in branches.

It has become widely known as one of the biggest miscarriages of justice in UK history and led to calls to scrap the legal presumption that computer evidence is accurate. 

In 1999, the presumption was introduced into law on how courts should consider electronic evidence. The rule followed a Law Commission recommendation that courts should presume a computer system has operated correctly unless there is explicit evidence to the contrary. This replaced Section 69 of the PACE Act 1984, which stated that computer evidence should be subject to proof that it was operating properly.

The 12-week call for evidence will invite views on the presumption from across the justice system and beyond, including from computer experts.

Justice minister Sarah Sackman KC said: “We must learn the lessons of the Post Office scandal. A blanket ‘no questions asked’ acceptance of the accuracy of digital evidence can have a devastating impact on people’s lives.

We must learn the lessons of the Post Office scandal. A blanket ‘no questions asked’ acceptance of the accuracy of digital evidence can have a devastating impact on people’s lives

Sarah Sackman, Ministry of Justice

“We need to carefully consider how we can both use and interrogate digital evidence in court. Ensuring people are protected from miscarriages of justice is vital, and one part of the government’s Plan for Change,” added Sackman.

Stephen Mason, who has campaigned for the presumption to be scrapped and co-edited Electronic evidence and electronic signatures, the open source practitioner text for judges and lawyers, said: “This call is overdue but most welcome. I and my colleagues look forward to engaging in the discussion.”

Peer James Arbuthnot, who along with colleagues in Parliament has been pushing for changes to the rules on computer evidence, welcomed the call for evidence. “They’ve got to do more than ask for evidence,” he said. “They’ve got to treat it properly and come up with some solutions because we’ve been making all the running on this and it’s time that the government actually did something.”

Arbuthnot campaigned for justice for subpostmasters for nearly two decades after his constituent, Jo Hamilton, was convicted of false accounting by the Post Office. Hamilton, who along with others helped expose the Post Office scandal as one of the biggest miscarriages of justice in history, had her wrongful conviction overturned in 2012.

Hamilton told Computer Weekly: “It should not be up to the accused to prove that the computer wasn’t working at that moment in time. The prosecution should have to prove it was. The law needs to be changed.”

According to the Ministry of Justice announcement, the call for evidence is seeking “expert input on how computer evidence should be defined, and what could fall into scope of any change to the law”.

It gave an example that distinctions might need to be drawn between “general digital evidence like text messages or social media posts, and evidence which has been specifically generated by a computer system or software”.

Court of Appeal judge Peter Fraser, who took charge of the 2018 High Court battle between the Post Office and 555 former subpostmasters that focused on the reliability of the Post Office Horizon system, spoke at a recent Inner Temple talk, titled “The use of electronic evidence in the law”.

He said the Law Commission presumption, which found its way into statute nearly 30 years ago, needs to be replaced, but its replacement is not a simple choice. “It’s very difficult to know now how courts in the future – the next 10, 20, 30 years – are going to deal with computer-generated evidence, or evidence from computers, or evidence about the operation of computers. What is important is being aware of what can be changed,” he told the audience.

“There needs to be some flexibility in how we approach it because the current complexity is just going to get more and more marked,” he added.

The Post Office scandal was first exposed by Computer Weekly in 2009, revealing the stories of seven subpostmasters and the problems they suffered due to the accounting software (see timeline of Computer Weekly articles about the scandal below).

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