Police told in 2016 that Post Office prosecutor withheld evidence of Horizon errors from court

Possible criminal offence

In his email to the police force in 2016, McCormack wrote: “I wish to bring to your attention what I consider to be a serious failure and possible criminal offence by a prosecution team during a criminal trial that took place at Guildford Crown Court in October 2010.

“It would appear that the prosecution failed to disclose material evidence to the defence, which is exacerbated by the fact that as prosecution, Post Office were responsible for the evidence in question. Post Office, as prosecutors, act under your supervision as far as I am aware, and are bound by your Code for Crown Prosecutors.”

McCormack drew the police force’s attention to the investigation report into the Horizon system produced by independent forensic accountants Second Sight in 2015, which revealed that in 2010 the Post Office knew, through an internal document, about software bugs that could cause unexplained accounting shortfalls.

In its 2015 report, Second Sight said it was “of potential significance” that it was not just an internal document made available to a small number of Fujitsu employees, but that the copy Second Sight was provided with was printed out by the head of the Post Office’s legal prosecution team in October 2010 – at the time, Singh.

As revealed in the latest public inquiry hearing, the document, which contained details of a series of bugs causing account discrepancies, was sent to Singh on 8 October 2010, just days before Misra went to trial. He saved it and printed it, but did not disclose the information to Misra’s lawyers.

In his email to the police, McCormack quoted the Post Office’s own documentation, which stated the Post Office had a “continuing duty to disclose immediately any information that subsequently comes to light which might undermine its prosecution case or support the case of the defendant”.

McCormack wrote: “Clearly the dates of these documents are relevant, as well as the fact that it was the head of Post Office legal prosecution team who printed them out in the same month [Seema Misra’s] trial was taking place.”

He said the disclosure of the documents highlighted to the Post Office by Second Sight would have had a significant effect on the outcome of the trial.

Surrey Police wrote back to McCormack informing him that the Criminal Cases Review Commission (CCRC) was investigating and that if it were to continue it would only be duplicating the CCRC’s efforts. “It has been confirmed that if the CCRC review finds any evidence of non-disclosure, they will pass their findings on to the police to move forward. If this happens, we would of course reopen our investigation,” said the police reply.

A few months earlier, McCormack had been labelled a “bluffer” by a senior Post Office lawyer when he wrote to former CEO Paula Vennells, warning he would go public about a Horizon bug that was causing unexplained shortfalls. Working with McCormack and others, Computer Weekly revealed the error, known as the Dalmellington bug, in November 2015. It was later used in the High Court as evidence when subpostmasters sued the Post Office.

A document containing details of a series of bugs causing account discrepancies was sent to Singh on 8 October 2010, just days before Seema Misra went to trial. He saved it and printed it, but did not disclose the information to Misra’s lawyers

Last week, Singh faced questions in the Post Office Horizon IT Inquiry, where documents revealed he was made aware of Horizon problems in the days before Misra’s trial. They confirmed that Singh received, saved and printed the information about Horizon problems, which was highlighted by Second Sight.

During the inquiry hearing, Singh said he didn’t “remember anything around that at all”. He said he didn’t remember whether details of the bug were disclosed to the defence or court in the trial.

Inquiry barrister Jason Beer KC said Singh was covering up his “guilty knowledge” of the bugs. “Surely you know about this? This case went off to the Court of Appeal, which ruled it was an error not to have disclosed it [and] the Post Office conceded that there should have been disclosure. And this is one of your cases that you prosecuted,” said Beer.

It was five years after McCormack’s 2016 email to the police before Misra’s conviction was overturned, and it was 14 years before Singh was questioned about it, during the latest public inquiry hearing last week.

Anatomy of a cover-up

Singh was close to decisions made by the Post Office to quash talk of Horizon problems, according to evidence in the latest inquiry hearing.

It was revealed that he agreed with a recommendation from colleagues that reports by Post Office investigators should not be disclosed to subpostmasters going through mediation.

In a 2014 email to colleagues, he wrote: “One of the dangers of investigation officers’ reports being disclosed is that it will always be easy for the applicant to think of something not specifically referred to in the report and allege that [the Post Office] investigation has not been sufficiently [thorough] or adequate. Of course, it is highly unlikely the investigation will have been deficient, but in the absence of a full set of papers it may become impossible for [the Post Office] to rebut such new allegations.”

During the email exchange, he referenced the prosecution of Jo Hamilton. The former subpostmistress in South Warnborough, Hampshire, was convicted of false accounting in 2006 after being threatened with a theft charge and, fearing a prison sentence, was pressured into pleading guilty to the lesser charge. In 2021, she had the wrongful conviction quashed at the Court of Appeal in a landmark case bearing her name.

In the 2014 email exchange, Singh told colleagues: “In the [Jo Hamilton] case, in the officer’s report, the investigation officer said: ‘Having analysed the Horizon printout and accounting documentation, I was unable to find any evidence of theft or cash-in-hand figures being deliberately inflated’.” Singh went on to explain in the email that this would give subpostmasters that were making claims “every opportunity to ask why in fact [Jo] Hamilton was prosecuted”, he wrote at the time. “In the absence of paperwork to deal with this, this would in turn cause [the Post Office] difficulties.”

Singh said he did not recall writing this, but when pressed by public inquiry chair Wyn Williams, agreed he must have known what was in the report about Hamilton’s case.

He was also involved in the creation of statements about Horizon’s reliability, which he referred to as “our story”. His statements were edited and amended by the public relations teams and ended up as witness statements used in prosecutions. Singh said he doesn’t know how this happened.

Beer KC asked how a “story” for agents and counsels to work to when resisting applications for a stay and resisting applications for adjournments or disclosure arguments got turned into a witness statement containing a statutory declaration.

Singh said: “I don’t know. I don’t recall, and I certainly didn’t have any part to play.”

With his head in his hands, Singh stooped during the hearing, a far cry from his self-congratulatory demeanour in 2010 after the Post Office succeeded in convicting Misra.

When Misra, pregnant, had to leave her husband and child for a prison cell, Singh sent a celebratory email to Post Office colleagues. He wrote: “After a lengthy trial at Guildford Crown Court [Seema Misra] was found guilty of theft. This case turned from a relatively straightforward general deficiency case to an unprecedented attack on the Horizon system. We were beset with unparallel [sic] disclosure requests by the defence. Through the hard work of everyone, counsel Warwick Tatford, investigation officer Jon Longman and through the considerable expertise of Gareth Jenkins of Fujitsu, we were able to destroy to the criminal standard of proof (beyond reasonable doubt) every single suggestion made by the defence.”

The Post Office wanted to use Misra’s conviction to send a message to other subpostmasters who were considering challenging the accuracy of Horizon figures.

The inquiry also recently heard that a former Post Office general counsel failed to give the CCRC evidence that would have identified the biggest miscarriage of justice years earlier. In a 2014 response to a CCRC request for an update on a Post Office review of its own prosecution strategy and processes, Chris Aujard, interim general council at the time, left out details that would have raised serious concerns over the safety of Post Office prosecutions.

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 Computer Weekly articles below).

• 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 •