Whether it's CCTV, mobile phones or GPS software, digital evidence now plays a role in almost every criminal trial, meaning that justice increasingly depends on people's ability to analyze technology and make arguments about what digital information means.
But experts talk about inequality. On the one hand, the prosecutor's office has its own service in the form of digital forensics units embedded in local police forces. But unless they are self-funded, defendants rely on legal aid to fund independent digital forensics.
To make matters worse, legal aid spending fell by 39.5% in real terms per person between 2010 and 2024, according to the Bar Council. As a result, there are few experts left capable and willing to take on criminal defense. “There is no equality of arms,” said Tim Forte K.S., a leading criminal defense lawyer. “Everything we do is limited unless it is privately funded.”
Westminster Forensic Science Commissionpublished in June this year, warned that restrictions on legal aid were putting justice at risk. Coupled with “over-reliance on police findings in digital investigations,” the report’s authors warned of defense bias.
Danny Kaye's story illustrates what can go wrong. The prosecution relied on digital evidence to convict Kay of rape in 2013, but it was only when relatives discovered deleted messages that a retrial was secured and his conviction was ultimately overturned.
In addition, prosecution experts used signal data from Jodi Rahn's phone to prove that she was at the scene of the arson and secure her conviction in 2015. It was only when a second expert demonstrated that Rana could have been much further away that the verdict was overturned.
Advocates fear these stories are just the tip of the iceberg. “We are constantly fighting for access,” Forte said. “It’s an ongoing battle where everything is trimmed.”
Restrictions on legal assistance
For many years, Forte's preferred forensic investigator has been Angus Marshall, a digital technology expert who also teaches at the University of York.
But Marshall no longer instructs defense lawyers because the fees he can claim back for legal assistance are so low.
In addition, the cost of accrediting an individual practitioner is very high. “I stopped doing business two years ago because of compliance costs,” Marshall said. “The figures given to me were somewhere between £10,000 and £30,000 and I will need to hire a quality manager. And my insurers will not insure me without this accreditation.”
In total Marshall turned over £25,000 a year for criminal defense, meaning the cost of accreditation would bankrupt his business.
Forte told Computer Weekly that when the defense can't find an independent expert to do the work, the trial is either postponed or continued. without any digital analysis to support the accused's version.
Computer Weekly's own analysis of court data found 4,264 cases where trials were postponed between 2020 and 2024 because the defense was unprepared due to the late disclosure of evidence.
Forte said independent experts like Marshall, with decades of experience, are being pushed out of the system.
Disclosure
Part of the problem, Forte said, is that the very devices analyzed in court are chosen by the prosecution.
Officers first seize digital devices they believe may be relevant to the case, and then a digital forensic investigator (DFI) compiles a list of those deemed relevant. The problem is that defense may think differently about what is important and what is not.
Ian Ross, a forensic psychologist and financial crime expert, says disclosure issues often arise in court. “Some things are institutional,” he suggested, citing his years working for Greater Manchester Police.
“Cops don’t like to be seen as losing cases,” Ross added. “I've seen many, many cases fail because of disclosure violations. People start fiddling around and playing games and hiding things.”
An analysis of Crown Court and Magistrates' Court data shows that 1,787 trials were postponed because the prosecution failed to disclose data between January 2020 and December 2024.
Regarding digital evidence, Ross said its technical nature is too often cited as an excuse for errors. “We get excuses about how busy everyone is and how technical it all is,” he said.
He referred to the infamous EncroChat trial, in which European police officers inserted malware into an encrypted messaging service widely used by criminals at the time. Officers made 1,240 convictions in 2020 but refused to reveal their hacking software. Ross said unless defense experts can forensically test their methods, any convictions will be unreliable.
For Forte, working in a system that fails to provide equal access to digital evidence is both “stressful” and “frustrating.” He spends most of his time “putting out fires.”
“For the last 10 years I've always said that I'm dealing with the crocodile closest to the boat,” he said. “Out of necessity, everything else is pushed into the background.”
A spokesperson for the Ministry of Justice (MOJ) said: “We understand the importance of high-quality, timely forensic evidence to an effective criminal justice system that prevents crime, prosecutes suspects and provides victims with the justice they deserve.
“That’s why we are appointing a national forensic director who will transform our approach to raising standards and efficiency and ultimately increasing public confidence in our criminal justice system.”
A spokesman for the Crown Prosecution Service said the agency had nothing to add to the Justice Ministry's statement. Forensic Science Regulator and National Police Chiefs Council did not respond to a request for comment.
