The Post Office's 1999 introduction of Horizon, a new computer accounting system intended to oversee transactions across the organisation, set off a chain of events culminating in the wrongful prosecution of hundreds of postmasters. The event, which we explore in this article, has come to be the most widespread miscarriage of justice in UK legal history – with repercussions still being felt years later.
The Horizon Error
Horizon was developed by Japanese software company Fujitsu with features intended to handle transactions, stocktaking and accounting. A 2003 document published by Fujitsu described the system as helping the Post Office and its branches to “become more efficient and improve their services by reducing customers' waiting time, simplifying procedures, and computerising traditional paperwork”. The system was rolled out in 1999 and its use continued well into the 2000s, with a full 11,500 branches making use of it by 2013. At this time, around eight million transactions were being processed by Horizon every day.
However, cracks in the system had begun to show as early as its debut year. Sub-postmasters who adopted the system reported unnerving errors, often involving significant quantities of money. Two of the most significant of these became to be known as the Callendar Square Bug and the Dalmellington Bug, the first of which generated false duplicate financial transactions that were considered the responsibility of the user rather than the database, and the latter of which caused the system to apparently lock up while users acknowledged receipt of a cash consignment, prompting said users to hit a key multiple times while unknowingly accepting responsibility for new consignments each time. Neither issue became public knowledge for more than a decade after Horizon’s introduction across Post Office branches.
On the back of these and numerous other bugs, the system began to report financial shortfalls from Post Office branches, which were again placed at the feet of the sub-postmasters who had taken Horizon on board. Some of the shortfalls ran into the thousands of pounds. Some sub-postmasters attempted to use their own money to bridge the gap, in some cases remortgaging their own homes, to little effect. The Post Office rejected claims that Horizon itself was at fault for the reported shortfalls, arguing repeatedly in statements that the system was “robust”.
Miscarriage of Justice
Sub-postmasters who were unable or unwilling to clear the deficits reported by Horizon were prosecuted by the Post Office. Claims of theft, fraud and false accounting were most common among these, with the majority of cases resting on IT evidence alone. In total, it is believed that between 2000 and 2014, 736 sub-postmasters were falsely convicted as part of the scandal; an average of one per week.
The impact of these false sentences has still not fully come to light, but many sub-postmasters were imprisoned following their convictions, while others were financially or reputationally ruined. Several reported the loss of subordinates’ jobs and the breakup of families in the wake of the artificially incurred losses. One victim is known to have committed suicide.
It is believed that between 2000 and 2014, 736 sub-postmasters were falsely convicted as part of the scandal; an average of one per week.
The debilitating bugs at the centre of the scandal were finally brought to light in the December 2019 Bates & Others v Post Office Ltd group litigation on behalf of more than 500 sub-postmasters prosecuted with IT evidence. Mr Justice Fraser found in his ruling on the lawsuit that software errors and defects in the Horizon system did exist and were sufficient to undermine its reliability in accurately processing and determining transactions, which had happened on multiple occasions.
Racial Discrimination
A further wrinkle was added to the case in May 2023 when a Freedom of Information request by justice campaigner Eleanor Shaikh revealed that suspects in the Horizon scandal had been grouped by racial features, with offensive terminology used in prosecutors’ official documentation. The document, which is believed to have been created in 2008, appears to show that the Post Office-appointed prosecutors tasked with investigating sub-postmaster shortfalls had been asked to group suspects in this way.
The document asked investigators if suspects were “N*****d types”. Other racial categories mentioned in the document included “Chinese/Japanese types” and “Dark Skinned European types”. The finding of the document spurred fresh outrage in the scandal, with several sub-postmasters questioning whether the cases pursued against them had been more severe due to this apparent racial motivation.
In a response to the FOI, the Post Office condemned the document’s “abhorrent” language, but described the findings as a “historic document”. “We fully support investigations into the Post Office's past wrong doings and believe the Horizon IT Inquiry will help ensure today's Post Office has the confidence of its postmasters and the communities it supports,” a spokesperson said.
The Outcome
Following the 2019 High Court ruling, there has been a widespread campaign to see justice for the sub-postmasters whose lives were upended by their wrongful convictions. 44 such cases were overturned in the Court of Appeal in December 2020, with a further 39 being quashed in April 2021 – with the rare finding that the appellants be completely exonerated, owing to the Post Office having acted in such a way as to subvert the integrity of the criminal justice system. The Post Office did not contest the appeals.
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Further, the Post Office has acknowledged the system faults at the heart of the Horizon scandal and apologised for the human cost incurred. In April 2021, Post Office chief executive Nick Read announced that the organisation would replace the Horizon system with a new cloud-based IT system, and a new independent inquiry was begun in 2022 to examine how the Horizon scandal came about.
Years later, however, the Post Office scandal continues to make national headlines. Shortly after the aforementioned 2023 FOI findings, a July report found that 438 sub-postmasters’ applications for compensation remain unresolved. Several of those wrongly convicted have since died without having their names cleared or receiving their due payout. The Post Office scandal has shocked the British media and public, and it may take many more years before the full scope of the injustice becomes apparent.
