Changes to law on digital evidence must not go too far

In light of the Post Office Horizon scandal, a review of the common law presumption that ‘the computer is always right’ in criminal proceedings was welcomed by CILEX in its response to a call for evidence issued by the Ministry of Justice (MoJ).

The response on the use of evidence generated by software in criminal proceedings acknowledged the importance of scrutinising all digital evidence, particularly in the light of technological developments such as artificial intelligence, and said reforms must “ensure trials are fair and convictions are safe”.

CILEX stressed, however, that “forcing all computer-generated evidence to be proven to be working correctly for each trial could be an unnecessary burden on parties, and especially on prosecutors. This would result in substantial costs for whichever party was seeking to introduce the evidence and additional costs for parties who are required to instruct expert witnesses.”

This, CILEX cautioned, was a key consideration given the current criminal court backlog of over 74,000 cases.

Both experts and statements of truth would be key to ensuring judges had “the necessary confidence” in the evidence and that it was “suitably probative”. CILEX stressed the need for “suitable renumeration and support” to minimise the burden on practitioners and on parties.

Despite these concerns, CILEX acknowledged the difficulties would lessen over time as “it would quickly become established practice that certain thresholds and evidence were required to demonstrate the integrity and condition of the computer-generated evidence”. Once established, practitioners would adjust.

CILEX supported defining computer-generated evidence within the Criminal Procedure Rules and advocated for the re-introduction of a considered and amended section 69 of the Police and Criminal Evidence Act 1984, with some caveats, namely that evidence should not be treated as computer generated if it is merely typed on a computer, duplicated electronically or is held or stored on a computer.

Then CILEX president Yanthé Richardson said: “The devastating miscarriages of justice that resulted from the use of flawed computer-generated evidence in the Post Office Horizon prosecutions, along with the significant developments in technology we have seen over the last 20 years, mean a review of this area of the law is much needed.

“It is vital we make the changes necessary to ensure our laws are fit for the modern age and that digital evidence can be trusted and relied upon in court. We must, however, take into account the additional cost and resources that would be required by those submitting digital evidence, ensuring the definition of such evidence is not drawn too widely and that necessary training and support is available to practitioners ahead of any change.”