The use of computer evidence in court

A press release from the Ministry of Justice has announced that the role of computer evidence in the criminal justice system will be examined through a call for evidence which launched on Tuesday 21st January 2025.

What is a call for evidence?

A call for evidence is an information-gathering exercise that seeks expertise from people, organisations and stakeholders with knowledge of a particular issue.

What is the current law?

Prior to 2000, the admissibility of computer evidence was dependent on whether it could be established if there was improper use of the computer, or that at all material times the computer was operating properly. After 2000, it was replaced with a common law (rebuttable) presumption that the computer was operating correctly at the material time. The presumption is a rebuttable one, meaning that if it can be shown that the software may not have been functioning correctly, the burden shifts to whoever is seeking to rely on the evidence to prove that it was.

Why a call for evidence?

In this instance, the call for evidence will last 3 months (open until 15th April 2025), with the intention that any proposed reforms will be informed by all available evidence. This has been enacted following the wrongful convictions of hundreds of innocent sub-postmasters in the Post Office Horizon scandal, which highlighted that there are potential dangers in the default position of assuming that a computer is correct. This assumption may lead to miscarriages of justice on a large scale, especially where this allows for a computer system used on a large scale to evade criticism.

Since the introduction of the rebuttable presumption, what constitutes digital material has evolved significantly, and the call for evidence seems particularly relevant given the swiftly evolving use of technology, including the increasing use of artificial intelligence. Therefore, it is important that the role of these more novel technologies that fall under computer evidence are open to scrutiny.

What does the call for evidence invite comment upon?

In the Horizon Post Office scandal, the failure to investigate properly meant that there were barriers to challenging this rebuttable presumption. Perhaps the call for evidence will reform the law in order to eliminate barriers to challenging said presumption, specifically by asking the following question that the call has welcomed answers and opinions on:

“1) The current common law (rebuttable) presumption is that computers producing evidence were operating correctly at the material time.

• (a) Is this presumption fit for purpose in modern criminal prosecutions?
• (i) Please specify why you gave this answer
• (b) How easy or difficult do you believe it is at present for this presumption to be effectively rebutted?
• (c) What barriers do you see in effectively rebutting this presumption?”

This expert review therefore aims to help build on the government’s efforts to restore public confidence in the criminal justice system. The call for evidence is open to the views of “all those with an interest in this area of criminal procedure,” thus with such a wide scope, it will almost certainly provide further insight into the use of computer evidence.

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