By South Warnborough is a sleepy village in the south of England. With a population of just 600, it has a pub, a church, and a village shop with a Post Office counter for sending and receiving mail, paying bills, and banking. In 2001, Jo Hamilton and her husband David — on the recommendation of other villagers — took over the shop. They operated a tearoom and delicatessen, sold groceries, and Jo became what is known as a sub-postmaster, running the Post Office counter.
Like thousands of other sub-postmasters across the country, Hamilton was using a new automated accounting software to track transactions, adopted in 1999. The UK government — the Post Office’s only shareholder — implemented the system, known as Horizon, to replace traditional paper-based accounting practices. Developed by Fujitsu, Horizon was, at the time, the biggest non-military IT project in Europe.
What Hamilton didn’t know is that she was about to become part of what would later be described as one of the greatest miscarriages of justice in British history. The Horizon system was faulty, and quickly started to cause unexplained shortfalls in sub-postmasters’ accounts. “Rather than investigate the problems and fix them,” tech publication Computer Weekly wrote, “the Post Office blamed the branch operators.”
On a number of occasions, Hamilton was faced with accusations that she had caused the shortfalls. “I was always told I was the only one having problems and that my contract said I had to make the shortfall good,” she tells GIJN. Eventually, the deficit grew to £36,000 (US$44,000). “The audit team arrived and demanded to know where the money had gone,” she recalls. “I was charged with theft and it took two years to drag me through court.”
After taking a last-minute plea bargain to avoid jail, Hamilton was ordered to pay the shortfall and had to remortgage her home to do so. “The judge spared me prison because 74 people from the village were in court to support me,” she explains. “I was, however, a convicted criminal, and would remain so for the next 14 years. A criminal record has far-reaching consequences. It restricted my work and my ability to help out with things at my granddaughter’s school. The list is endless.”
Hundreds of other sub-postmasters were also criminalized. Fiona McGowan was accused of stealing £30,000 (US$36,500) while running a Post Office in Edinburgh, Scotland. It ruined her reputation within the community, and her mental health began to plummet. “She went from running successful businesses to dying alone and penniless in a homeless shelter,” ITV News wrote. “She was just 47.”
Sub-postmaster Martin Griffiths had to pay the Post Office £102,000 (US$124,000) following similar accusations of shortfalls. In 2013, he “deliberately walked in front of an oncoming bus,” his wife told a 2020 government inquiry into the scandal. He never regained consciousness and died three weeks later. The UK Post Office scandal represents the biggest single series of wrongful convictions in British legal history. There were 900 prosecutions for theft, fraud, and false accounting.
Breaking the Silence
In 2009, the first story about the Post Office’s IT problems hit the press. It wasn’t a headline on TV news channels or on the front pages of the newspapers. In fact, it was in Computer Weekly, a now-digital (but formerly print) specialist magazine for tech and IT professionals. Journalist Rebecca Thomson wrote about Lee Castleton — a sub-postmaster who was sued and bankrupted by the Post Office after his accounts showed discrepancies — alongside six others, including Jo Hamilton. The piece was the result of a year-long investigation.
Tony Collins, who was Computer Weekly’s executive editor at the time, had broken a number of stories on IT errors. He first became aware of the Horizon issue after receiving a letter from sub-postmaster Alan Bates in 2004.
“Collins wrote a lot about public sector IT disasters and IT outsourcing,” Karl Flinders, chief reporter at Computer Weekly, tells GIJN. “When someone contacts you, you know, it’s hard to handle the story of one person. But he kept [Alan’s letter] in his mind, and put it aside. And then in 2008, he was contacted by Lee Castleton, who is another well-known sub-postmaster, telling a similar story.”
Collins worked with Thomson to write the first article. “Obviously, it was a bit of a risk,” Flinders says. “We weren’t as worried about being sued by the Post Office, because it’s a government organization, so less likely. But Fujitsu, they could have sued us in damages if we got things wrong.”
Computer Weekly picked up the story early, but it would take a long time for the national papers to show any interest. Their first story, from 2009, detailed the cases of seven sub-postmasters who had experienced problems with the IT system. Image: Courtesy of Computer Weekly
Thomson left Computer Weekly in 2010, and Flinders continued reporting. The investigation wasn’t picked up by national outlets initially, but Computer Weekly kept at it. “We love doing off-diary investigations,” Flinders says. “It was slowly, gradually, picking up more steam. And obviously, Alan Bates was behind the scenes with a group of sub-postmasters doing all of their work [to clear their names]. We were working with them; writing about them.”
In 2018, a landmark court case saw 555 sub-postmasters take on the Post Office. They were successful in proving that Horizon was defective, which Flinders says was a turning point in the investigation. “Since then, a lot’s been in the open,” he says. “Still, they didn’t really pick it up that madly, the newspapers.”
Everything changed in 2024 when the broadcaster ITV produced a hit dramatization of the scandal: Mr Bates vs The Post Office, which focused on the sub-postmasters’ campaign for justice. It became the channel’s most-watched show of the year, with more than nine million viewers. The public outrage was palpable and the government was forced into action, later announcing that they would introduce legislation in order to exonerate the hundreds of convicted sub-postmasters collectively.
“Mr. Bates vs The Post Office” became ITV’s most-watched show in 2024. Image: Courtesy of ITV Studios
Sticking With the Story — Even If It Isn’t ‘Sexy’
Another outlet that chipped away at the Post Office scandal before it became wider public knowledge was satirical and current affairs magazine Private Eye. Investigative journalist Richard Brooks had been writing about the software errors since 2011, after the publication received a call from journalist Nick Wallis. Wallis had done a local news program about the issue, and interviewed a number of sub-postmasters.
“He thought that this was an important story, and wanted it to get some wider coverage,” Brooks says. “I thought it was very interesting because over the years, we’d covered a lot of government IT cock-ups.”
Private Eye had previously reported on the Horizon project, but as a public spending matter, Brooks explains. “This seemed like the consequences of what we’d been writing about all these years,” he tells GIJN. “And I thought, these stories really impacted people’s lives, and it was important for us to take it up. I mean, to be honest, I was slightly disappointed that we hadn’t picked up on it earlier, given the interest that we’d had in these issues.”
A unique element of the investigation for both outlets was that the sub-postmasters were simultaneously working as a campaigning group, the Justice For Subpostmasters Alliance (JFSA). The JFSA operated as “the workhorse” behind the campaign to expose the failures of the Post Office and the cover-up that came with it. Founded by Alan Bates, the group were submitting Freedom of Information requests, preparing for legal action, and pushing for a national inquiry.
“It was different to a normal investigation that I would do in that I wasn’t bombarding the Post Office with lots of questions,” Brooks explains. “[The JFSA] were getting access to far more information than I ever could. I thought the best job we could do was to keep the profile of that campaign, that effort, up, so that it became a political matter.”
Brooks reflected on why it took the story so long to break through to national outlets. “It wasn’t a sexy story. I mean, it was computer systems,” he says. “It was people whose plight didn’t really bother big newspapers all that much. Certainly not as much as it should have done. I think if there had been a bit more bling in the story, the papers would have been all over it. But these were very ordinary people. Unglamorous. And, you know, that didn’t appeal as much as it should.”
‘They Underestimated Us’
Flinders’ advice for investigative journalists is to build up a network of contacts, and continue speaking to those closest to the story. When interviewing IT experts for other stories, he would always keep the Horizon scandal in the back of his mind, he says, asking them if they had any knowledge of the software and its issues.
“Speak to as many people as you can, never think a story might be too outrageous to be true, and never ever give away your sources, or even hint at what they could be,” he adds. “Be really thorough, go through everything, double check, triple check, and stick with it, you know. Because this story – for a couple of years, there wasn’t much happening. It was really frustrating, but just always keep it there in the background when you’re doing other things.”
He acknowledges that small or niche news outlets can face different circumstances. “Being a small team, we can’t really risk going to court, because it would destroy us,” Flinders explains. But he also says that it brings advantages. “I think they underestimated us… They didn’t really see that we could do them any harm. They think if Computer Weekly write it, it’s a small outfit, who cares?”
In the case of Private Eye, Brooks emphasizes the value of perseverance. “We did stick with it for over a decade; we regularly kept it in the public eye,” he says. “Lots of other angles like who was involved, the hypocrisy, why they might be doing it – looking beyond just the facts of individual cases to broaden the perspective. To say, well hang on a minute, what were the commercial imperatives of the Post Office? Why were they doing this?”
Cultivating a range of contacts was also a core part of Private Eye’s coverage. “If people are getting the details beyond what you could get just by asking for it yourself, then clearly you want to get in with them,” Brooks says. “There is a bit of a balance between developing good relationships with people and your journalistic objectivity. You’ve got to manage those two things.”
Investigative journalist Karl Flinders. Image: Courtesy of Flinders
Something that both Flinders and Brooks highlight is that journalists working on similar stories should set reasonable expectations. “There’s no guarantee that scandals will get exposed and dealt with,” Brooks notes. “As a journalist, you’ve just got to do your job. There’s some satisfaction when things get noticed, but that’s not always going to happen. You’ve got to get your job satisfaction from just doing it.”
Last year, the Post Office said that it was “sincerely sorry for the devastating impact” that unreliable Horizon data had caused hundreds of sub-postmasters. As of January 2025, the UK government has paid approximately £594 million (US$733 million) in financial redress to over 3,800 victims, and more than 2,000 new compensation claims have been made in the last month by others. Fujitsu has also issued an apology, and admitted that they have a “moral obligation” to contribute to compensation efforts.
In 2024, Computer Weekly won an Orwell Prize “for breaking the Post Office Horizon scandal and sustained investigation and reportage of the story over many years.”
While the award was welcome recognition of 15 years of dogged reporting, for the journalists behind the story, the real win has been in making sure that the voices of victims have finally been heard.
“That’s why most people become journalists. I can’t believe that I’ve been able to work on a story like this,” Flinders says. “99.9% of leads that I work on off-diary don’t come off, but if you get one like this, it’s worth it. Even if you think it’s not going anywhere, never just give it up completely. If you trust your sources and you believe it’s true, just keep plugging away.”
