- Author, Nalini Sivathasan, Lorna Acquah and Emma Simpson
- Role, BBC news
A former Fujitsu engineer who helped design the flawed Horizon software at the center of the Post Office scandal will take center stage this week.
You may not have heard of Gareth Jenkins until now, but he became a key figure during the long-running Post Office investigation.
He will be questioned at an inquiry into his involvement in the scandal, which saw more than 900 sub-postmasters wrongly prosecuted between 1999 and 2015 after Horizont said the money was missing from branch accounts.
Mr Jenkins will testify over four days – the longest series of questions a witness has faced. Here’s why what he has to say is so important.
The so-called “architect” of Horizon
Its appearance is highly anticipated as it has been delayed twice.
A top lawyer working for the Post Office once described Gareth Jenkins as an “unreliable god”, an inquest heard.
“His name came up repeatedly during these hearings, often many times a day,” says David Enright, a lawyer at Howe & Co, which represents many of the victims.
He believes Mr Jenkins will be “subjected to the most extensive questioning” at the inquest.
It failed to detect errors and remote access
Since 2005, Mr. Jenkins has been instrumental in helping the Post Office defend its flawed computer software system in criminal and civil cases.
“He was Fujitsu’s go-to expert on any reliability issue,” says David Enright.
In 2010, Mr Jenkins gave evidence at the trial of Seema Misra at Guildford Crown Court.
She told the BBC: “I was naive at the time. I thought it was good that he worked for Fujitsu because he would know the system inside out.
“If something went wrong in Horizon, he would see it.
What Ms. Misra did not know was that Mr. Jenkins had flagged a bug that affected dozens of branch accounts shortly before the trial and that he had suggested remote access to their computer terminals as one way of solving the problem.
Mr Jenkins did not disclose this in court. Ms Misra was found guilty of theft and false accounting and was sent to prison while pregnant.
If the problems were discovered then, it could have stopped all prosecutions in their tracks.
Two years later, lawyers representing Deputy Postmaster Kim Wylie asked about remote access. Seeking advice on what to say, Mr Jenkins warned the Post Office’s lawyer that including the option could lead to more scrutiny.
His latest witness statement confirmed that this could happen and in his final version he went on to say that altering branch accounts in this way was rare and had to be approved by post.
He was supposed to be impartial in court
Mr. Jenkins appeared as an expert witness in a number of criminal prosecutions of subordinate postal authorities.
The law states that experts must be independent and impartial. However, the inquest found evidence that Mr Jenkins was never properly instructed in his duties by solicitors.
Documents obtained by the BBC earlier this year showed that the Post Office prosecutor suggested that Mr Jenkins rephrase some of his trial evidence against Seem Misra, bolstering his claims about Horizon’s robustness.
IT expert Jason Coyne, who was once used as an expert witness in the Post Office case, believes Mr Jenkins was someone the Post Office could “manage”.
“Sometimes we call people ‘hired guns.’ There is a risk that the post office was trying to do with him,’ says Mr Coyne.
The BBC understands that Mr Jenkins has been involved in at least 15 Post Office investigations.
From “Tainted” Witness to “Shadow Expert”
By 2012, independent forensic investigators Second Sight were brought in to examine the Horizon system.
At the time they praised Mr. Jenkins’ “super” expertise – they didn’t know that his evidence was used in the courts.
However, soon after their interim report revealed several errors, the Post Office received legal advice which warned that Mr Jenkins’ previous omissions had “fatally undermined” his credibility as a forensic expert and they should stop using him.
But Mr Jenkins remained a key figure behind the scenes.
He provided technical support and information to witnesses who testified in the Bates v Post Office trial in 2019, despite not being called to testify.
During the trial, lawyers representing the subpostmasters described him as a “shadow expert” – someone who advises but does not testify in court.
The Post has been criticized for failing to acknowledge that his absence may have been linked to concerns about his evidence in past criminal prosecutions.
The judge, Mr Justice Fraser, recommended that the head of the Crown Prosecution Service open a perjury investigation against Mr Jenkins.
His expertise came at a price
As part of the contract with the post office, Fujitsu provided support for legal cases involving the Horizon system.
But this did not always cover Mr Jenkins’ work, so the Post Office had to pay extra.
The inquiry heard sometimes played a role in whether the Post Office had adequately investigated concerns about shortages at sub-postmaster branches.
When Sub-Postmaster Grant Allen noticed a £3,000 shortfall at his branch in Cheshire, a lawyer working for the Post Office asked Mr Jenkins to estimate two days of data analysis.
In December 2012 emails released to the poll, Mr Jenkins replied that “data up to 7 years is freely available. Two days of my time costs around £2,000 to £2,500.”
The decision to perform data analysis was ultimately rejected.
The BBC has passed the content of this story to Mr Jenkins. A lawyer representing him said it would be “inappropriate” for him to comment before giving evidence at the inquest.
The Post Office said it had “profoundly apologized” to the victims and “remained focused” on supporting the ongoing investigation.
Fujitsu declined to answer specific questions from the BBC, but said it was “taking this matter with the utmost seriousness”.