An amendment proposed to remove the presumption that computers are reliable
An amendment to the controversial rule that courts presume computers are reliable was formerly proposed during a House of Lords debate on 11 February.
Since 2019, there have been calls for change following the exposure of the Post Office’s misuse of the rule by Sir Alan Bates and the Justice for Subpostmasters Alliance members to prosecute subpostmasters.
The debate featured peers James Arbuthnot and Kevan Jones, who introduced the amendment to remove the presumption. The pair have been long-time campaigners for justice for subpostmasters affected by the scandal.
Peer Shami Chakrabarti moved the amendment during the debate to eliminate the presumption that computers are reliable, which was introduced in 1999 under section 69 of the Police and Criminal Evidence Act 1984. This enabled the Post Office to prosecute subpostmasters using unreliable evidence.
Chakrabarti highlighted during the debate the importance of scrutinizing computer evidence and how the repeal of the protection in 1999 has led to serious harm, particularly in cases like the Post Office Horizon scandal.
The government, pressured by public outcry over the scandal, introduced legislation in 2024 to overturn wrongful convictions in the Post Office Horizon case.
Arbuthnot emphasized that evidence derived from computers should be treated with caution, as presuming it to be reliable is a significant step.
Following the debate, government minister Jason Stockwood’s response to a query on the proposed change was ambiguous, leaving uncertainty about the government’s stance.
IT professionals are in agreement that the logical conclusion would be to remove the presumption of courts that computer evidence is reliable.
The government launched a call for evidence in 2025 to examine the use of computer-generated evidence in criminal proceedings and is currently reviewing responses.
The Post Office scandal, first reported by Computer Weekly in 2009, exposed the injustices faced by subpostmasters due to issues with the Horizon accounting software.
