Ignorance of ‘legal niceties’ from Post Office expert IT witness saw innocent people jailed


A former Fujitsu IT expert’s ignorance of the rules that expert witnesses to courts must adhere to meant subpostmasters were wrongly convicted of financial crimes and jailed, the Post Office public inquiry has heard.

Gareth Jenkins began acting as an expert IT witness to courts for the Post Office in the early 2000s, when the organisation was using computer evidence to prosecute subpostmasters who had unexplained shortfalls, but Jenkins revealed he did not actually understand the responsibilities attached to the role until 2020, years after he ceased to be an expert witness.

As a result of his lack of understanding, he focused on information on specific cases, which was too narrow, and ignored known software problems that he wrongly believed were out of scope. He was also influenced into changing statements by Post Office lawyers.

Jenkins, a mathematics graduate from Cambridge University and former senior engineer at Fujitsu, was a senior IT expert working on the Horizon system used in every Post Office branch. He gave evidence in 15 prosecutions of subpostmasters up to 2013, when the Post Office was advised by a barrister to no longer use him as he had given misleading evidence in the past.

During the first day of his four-day inquiry appearance, Jenkins said he never received advice about his responsibilities as an expert witness. “The first time I became aware of my duties as an expert witness was when I was first put in touch with solicitors in 2020/21 as part of the police investigation into my conduct,” he said.

Jenkins is currently under investigation by the Metropolitan Police for potentially committing perjury during the prosecutions of subpostmasters. The police launched its investigation into Jenkins and former Fujitsu colleague Anne Chambers in November 2020, after High Court judge Peter Fraser referred them to the Director of Public Prosecutions.

During the hearing, Jenkins said: “All I thought I had to do was answer the questions and that the answers had to be truthful. I am a technician and I was more concerned about the facts of how the system was working rather than the legal niceties, if you like.”

Understanding of duty

Highlighting the obligations for expert witnesses, Jason Beer, KC to the public inquiry, asked Jenkins: “Did you understand you were under a duty to draw to the attention of the court all matters which might adversely affect your opinion?” This would include his knowledge of bugs in the Horizon system. Jenkins said he didn’t understand that.

Beer said: “You thought you were entitled to keep to yourself matters that might adversely affect your opinion, answer the narrow question that was asked of you?”

“Yes, nobody told me I needed to do more than that,” replied Jenkins.

Jenkins was asked whether he thought he was only required to tell the truth and not the whole truth in his witness statements. “I was talking about those aspects that related to the Horizon system, and I believe I did tell the truth and the whole truth as far as the Horizon system was operating in the specific branches at the specific time that I looked at the data.”

Beer said: “But you didn’t feel under any compunction to volunteer information about other faults or system defects about which you had not been asked.”

The inquiry also heard that although Jenkins said he had no specific instructions about his duties as an expert witness, as part of his role he reviewed the expert witness reports from the defence teams of subpostmasters which had clear expert declarations within them that made it clear the legal responsibilities of someone performing the expert witness role.

Beer asked: “Did you think, ‘Hold on, I keep reading these reports from other guys and they keep saying this stuff at the beginning and end of their statements about the duties they are under, does any of that apply to me?’”

Jenkins said:  “It didn’t occur to me that this applied to me.” His naivety meant his statements were used in prosecutions that saw innocent people sent to jail, including Noel Thomas, who spent his 60th birthday in prison, and Seema Misra, who was pregnant with her second child when convicted and jailed. Both former subpostmasters had their wrongful convictions overturned in the Court of Appeal in 2021.

Lawyer influence

Jenkins was also influenced by Post Office lawyers when making his statements, the inquiry heard.

Beer asked him whether he understood that he was not permitted to include matters suggested to him by anyone else, including the lawyers, in documents submitted to the court.

Jenkins said: “No, because certainly we have seen in some cases there were comments made on my reports, by the lawyers, and I actually changed things there as a result of some of those comments. Therefore, I didn’t think there was anything wrong with doing that.

“Obviously, if I disagreed with the comments, I wouldn’t change things, but if I was happy to agree with the comments and it didn’t detract from what I was trying to say, then I was happy to accept suggestions of how my wording could be improved,” he added.

Jenkins also told the inquiry that Post Office lawyers tried to put words in his mouth.

The Post Office scandal was first exposed by Computer Weekly in 2009, revealing the stories of seven subpostmasters – including Alan Bates – and the problems they suffered due to accounting software. It’s one of the biggest miscarriages of justice in British history (see below for timeline of Computer Weekly articles about the scandal, since 2009).


• Also read: What you need to know about the Horizon scandal •

• Also watch: ITV’s documentary – Mr Bates vs The Post Office: The real story


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