Fujitsu’s Post Office Horizon admission was ‘bombshell’ amid ‘religious panic’ over reliability

Barrister Simon Clarke was representing the Post Office when he discovered an expert witness had misled courts in subpostmaster trials

Karl Flinders,
Chief reporter and senior editor EMEA

Published: 09 May 2024 15:00

A Fujitsu IT expert’s admission that bugs existed in the Post Office Horizon system in 2013 was a “bombshell moment”, according to a barrister who was acting for the Post Office at the time.

Simon Clarke, a barrister who advised the Post Office on criminal prosecutions, also told the Post Office scandal public inquiry that there was “an almost religious panic that Horizon must not be seen to have been impugned”.

Over 700 subpostmasters and their staff were prosecuted and convicted over unexplained accounting shortfalls in their branches, based on evidence from Horizon. These shortfalls were later proved to have been caused by errors in the Post Office’s accounting system, supplied by Fujitsu.

During the latest Post Office scandal public inquiry hearing, Clarke was asked by inquiry barrister Julian Blake about the moment he was told by the expert witness – used by the Post Office when prosecuting subpostmasters – that he was aware of software bugs but had failed to reveal this to court.

Clarke, who worked as a barrister at Cartwright King, which was contracted by the Post Office to provide criminal prosecution support, had requested a meeting with a Fujitsu expert after forensic investigators Second Sight had identified two software bugs that could affect branch accounts. He recorded the telephone conversation with Fujitsu’s chief architect, Gareth Jenkins, because he felt it “hugely important” to ascertain who told Second Sight about the Horizon bugs. A transcript of the conversation was revealed in the latest public inquiry hearing.

During the July 2013 conversation, Jenkins told Clarke there were two confirmed bugs in the Horizon system, and that he could not say there weren’t more, Clarke told the latest public inquiry hearing. “What [Jenkins] had been saying in his previous statements was contrary to what he said here,” he added.

“He knew at the time of this [July 2013] conversation and beforehand that those bugs were extant because it was he who had informed Second Sight; that to me was the most important element in the conversation,” said Clarke. Put to him by Blake that this was “quite a bombshell moment”, he agreed.

Wrongful conviction

Jenkins gave evidence of Seema Misra in 2012. Misra had challenged the Horizon system as part of her defence, citing Computer Weekly’s 2009 investigation into Horizon errors, but Jenkin’s evidence convinced a jury of her guilt. She was convicted and jailed for 15 months, and had her wrongful conviction overturned in 2021.

Clarke is known to the inquiry due to advice he gave the Post Office prosecutors in 2013, stating that Jenkins was an unreliable witness who gave unreliable evidence in court and should no longer be used as a witness when prosecuting subpostmasters.

During the latest hearing, Clarke was drawn to his witness statement to the inquiry by Blake, which recorded Clarke’s opinion of the Post Office’s attitude to disclosing evidence during prosecutions of subpostmasters.

In it, he said: “Looking back I now see what appears to be three strands of thought within the Post Office on the topic of disclosure.”

He said the first “amounted to an article of faith that Horizon is both robust and reliable”, and that if it says money is missing then money is missing. The second strand, he said, considered that the cost of providing disclosure was prohibitive and should always be discouraged, while in the third he described “an almost religious panic that Horizon must not be seen to have been impugned”.

The Post Office scandal was first exposed by Computer Weekly in 2009, revealing the stories of seven subpostmasters and the problems they suffered due to accounting software (see timeline of all Computer Weekly’s 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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Police told in 2016 that Post Office prosecutor withheld evidence of Horizon errors from court