Horizon: Lessons Learnt? Highlights from Archives of IT's 2026 Forum

Main image: Archives of IT 2026 Forum panel. Top right, Bryan Glick; middle right, Richard Brooks; bottom right, John Carrington; bottom middle, Richard Brooks’ book, bottom left, Sir Kenneth Olisa. Report by Adrian Murphy

How can reasonable people do this? One of the poignant questions posed at Archives of IT’s 2026 Forum, which took place last week at the Worshipful Company of Information Technologist’s Livery Hall in Central London and online.

Focusing on the Post Office Horizon IT scandal, the Forum explored what we have gleaned so far from one of the UK’s greatest miscarriages of justice, which resulted in more than 700 sub-postmasters being prosecuted due to a defective Horizon IT system. The event was jointly hosted by AIT and the WCIT’s Ethical & Spiritual Panel and compered by Richard Harvey, its chair and Professor of Computer Sciences at the University of East Anglia.

Keynote speaker Richard Brooks, a Private Eye journalist and author, gave a scathing overview of the immoral actions of figures from the Post Office, the government, Fujitsu and their legal teams that have led to wrongful convictions of innocent citizens during a scandal that began in the late 1990s and is still ongoing.

Post Mortem

Brooks, who relentlessly pursued the fallout of the scandal from 2010, recently published a book, Post Mortem: the Post Office Horizon IT Scandal, which is a forensic look at ‘how the Post Office, the British government and a global IT company ruined the lives of thousands of innocent people’. The book includes a forward by Sir Alan Bates, former sub-postmaster and leading campaigner for the victims of the scandal.

One of the motivations for writing the book, Brooks said, was to understand why when things go terribly wrong, not just in IT but in all areas of public life, we are deficient in analysing how the failure happened and what caused the problem. With Horizon the list is long and painful, from a large and impulsive government investment to inept coding and the discovery of fundamental faults in the system to the subsequent cover up and scapegoating of sub-postmasters.

Pulling together what happened

“My aim with the book was to start that process and to pull together what had happened.”

Also on the panel was Bryan Glick, the award-winning editor of Computer Weekly – the publication that uncovered the scandal in 2009 – who reminded the audience that, despite the continuing flaws in the IT system, the Post Office is still using Horizon and is likely to do so for many years with procurement of a replacement ongoing.

To offer their insight on the professional side of IT were two of the WCIT’s distinguished Past Masters, Sir Kenneth Olisa, Lord Lieutenant of London and AIT’s Chair of Trustees, John Carrington.

Carrington, who established the Ethical and Spiritual Development Panel 30 years ago, gave a brief introduction on behalf of AIT and said the charity appeared as a source for Brooks’ book and how it was imperative the archive covered important failures in the industry such as Horizon.

Master’s welcome to ‘gruelling’ conversation

To give a little perspective on the evening, Gus Machado, WCIT Master, said one of the themes that has become impossible to ignore during his tenureship was the growing concerns about ethics in IT, and what happens when technology goes wrong.

“And if you asked me to rank IT disasters and events where a system didn’t merely fail technically, but failed humanly, then the Horizon system would be among the very worst,” he said. “Normally, I would say enjoy the evening. But much of what we will hear tonight will be challenging. Perhaps gruelling. And yet, they are precisely the conversations that matter most.”

Timeline: The Post Office Horizon IT Inquiry recommended ‘full and fair’ compensation for sub-postmasters

False imprisonments and false evidence

Brooks started by trying to make ethics more tangible in the context of IT by reading what the judge said in the trial of Seema Misra OBE, a former sub-postmaster in West Byfleet, Surrey, who was falsely imprisoned in 2010, based on flawed Horizon evidence.

He said the judge’s instructions to the jury included this question: ‘Do you accept the prosecution’s case that there is ample evidence before you to establish that Horizon is a tried and tested system in use at thousands of post offices over several years, and is fundamentally robust and reliable?’ “And the jury did, and Seema Misra was found guilty and sent to prison while pregnant, and on her son’s 10th birthday. So that’s the depth of the scandal and the problem we’re dealing with, what it can mean to have false evidence, and in this case false IT evidence, set against you.” Seema was sentenced to 15 months in prison and gave birth while incarcerated.

Computer Weekly breaks the story

By the time Seema Misra was sentenced Computer Weekly had already written its first report exposing the scandal in 2009 with its former journalist Rebecca Thompson writing half a dozen case studies based on victims’ testimonies. She was awarded an OBE in January 2025 for her work uncovering their stories.

“And then I started looking at the cases, including Seema Misra’s and others such as Jo Hamilton’s [who founded Justice for Sub-postmasters Alliance]. “I wrote Private Eye’s first report on the scandal, linking it to a long history of flawed government IT projects specifically.

“[It included] a response from Mike Young, COO at the Post Office from 2008 to 2012. He said that: ‘The Post Office takes meticulous care to ensure that the Horizon computer system in branches nationwide is fully accurate at all times.’ Which he knew was nonsense, and anybody who had any involvement in IT knew was nonsense because computer systems aren’t fully accurate at all times. But such was the importance of not admitting to the problem, the lies were routine.”

One big lie from the start

Above is a link to Richard Brooks’ talk at AIT’s 2026 Forum

Brooks said the whole story was one big lie from the start and by 2011 it had become a lie that was being parroted to media and anybody who asked.

“Right from the outset, the origins of the Horizon project were not auspicious, to say the least.”

He traced Horizon back to the mid-90s as a program to transition benefit payments through an electronic card, which would automatically feed into an accounting system, so the two would be combined. This was an era, he pointed out, with great hopes for IT and the Governments of the time were short of money post-recession and pinned their hopes on producing a transformation in public services.

“The Department of Health and Social Security was a prime target. It could utilise this new IT system and would be set up with a private finance initiative (PFI) project, which was a way of funding investment without borrowing money. Both Conservative and Labour governments at the time (1996-1997) were particularly keen on this approach. But the problem with PFI was it was later found to be totally unsuitable for IT.”

He said that when it was all falling apart, the government brought in Sir Adrian Montague to investigate and he found as early as 1998 that there was some risk around scalability and robustness because the system had to be tested at the level of component parts, not as a whole.

Deception

“Then, when the decision had to be made on how to react to this, the Business Secretary at the time, Peter Mandelson, stepped in and said that there’d been an independent review and it had found it to be robust, which was a complete lie. They hadn’t,” said Brooks. “So from the start we were dealing with a deception. And things went from bad to worse once trials of the prototype system started in ’98 and ’99 across 300 branches. It got to the point where Fujitsu found there were, in one week, 2,451 differences in 67 outlets between what the system said there should be in an account and what there actually was.

“They knew from the outset that it was not working at the level it needed to. In fact, they were targeting a 0.6% transaction error rate and when you think how many millions and billions of transactions were going through the Post Office branch network that told them immediately that there was a lot wrong.

“It was so poor that Fujitsu set up a task force in 1999 led by a development manager and an IT auditor. And they concluded that whoever wrote the code clearly had no understanding of elementary mathematics or the most basic rules. The denial at a political level was to get the project going and to avoid the embarrassment of cancelling a £1bn project.”

Lies have consequenses/judges believe experts

But soon the lies started to have consequences on the lives of sub-postmasters, those who were being suspended and prosecuted for shortfalls, which had been wrongly highlighted by the faulty IT. In 2003, Julie Wolstenholme, a sub-postmaster at Cleveleys post office in Lancashire, had a shortfall, was suspended and said ‘this isn’t right’ and sued the post office. An independent expert, Jason Coyne, was appointed to examine the accounting system as part of the civil case and he said the system was clearly defective.

Following this another high-profile case made the headlines (Brooks said he could go on and on with examples of wrongdoing). It involved sub-postmaster Lee Castleton who was wrongly found guilty of decrepencies in 2007 and the Post Office spent hundreds of thousands of pounds to defend the IT system.

“So, they lied, mostly by omission, by not telling the court about known faults, even within that branch,” says Brooks. “But the judge, in deciding the case in favour of the post office said that the Fujitsu witness was clearly knowledgeable and reliable. So this is the power that experts have. Judges believe experts. And it’s very easy, or too easy, to pull the wool over the court’s eyes, which shows the legal aspects of the scandal are another very important area that needs addressing, but also the way that the industry expertise feeds into that.”

Turning a blind eye

Brooks says that he tries to address in his book how senior management could let this happen and he says it appears they were turning the proverbial blind eye.

“For example I reference Richard Christou’s interview with AIT, who was the CEO and Executive Chairman of Fujitsu from 2000 to 2007, and was extremely proud of his project. Christou led the negotiations on the Horizon project and when asked at the inquiry in 2024 whether the system was fit for purpose, he said that fitness for purpose was not part of the agreement. He didn’t even see the irony of it, nor the dark humour in it. He just thought, well, that’s fine, that’s my job, you know, so what. People went to prison and my job is to produce an IT system and get the money.”

He says that the commercial incentives at the time for both the Post Office and Fujitsu were quite strong. And then the Labour government also couldn’t afford failure for its own reasons.

“So there was an incentive not to know at the top, which seemed to transmit through the organisations into a direct lie. What challenged me a bit as I wrote this book was the question of how and why people would do that. Lying in a court. I mean, everybody knows how serious that is. It wasn’t so much skin off their nose, to tell the truth, I wouldn’t have thought. Why would they do that? And that must be deeply in the culture of an organisation that they group think.

More openess

“The explanation is difficult. What I tried to address is what can you do about it? And the conclusion I came to is that more openness is the answer. The people who are covering up, whether in the Post Office or Fujitsu need to fear that someone will say what is really happening. And we need people not to be tied up by non-disclosure, confidentiality agreements.

“I looked at the BCS, Chartered Institute for IT’s Code of Conduct and it says that members must not represent or withhold information on the performance of products, systems, or services, so that sounds good. And then in brackets, ‘unless lawfully bound by a duty of confidentiality not to disclose such information’. Well, it’s very easy for a company to impose a duty of confidentiality.

“It’s the big cultural change you need and I think there is an urgent need in IT, as there is elsewhere, to get to a position where speaking up becomes the norm and becomes a thing that is applauded rather than condemned.”

Horizon is the Post Office

Bryan Glick, a distinguished technology journalist and Editor of Computer Weekly, which ran the first exposé on Horizon, said it was remarkable that despite knowledge of the faulty IT sysyem and the devastation it had caused, it was still in place and still operating across the UK.

“You must remember that every time you go into a post office today, and your sub-postmaster is there, they’re still using Horizon. This same system is still in use. Horizon is the Post Office. If you switch off Horizon tomorrow. You switch off the Post Office.

“The Post Office today is so aware of and so open about the bugs in Horizon that if a sub-postmaster today reports a discrepancy in their accounts, it doesn’t question it, and they just write off the money,” he said. “So even today, there are tens of millions of pounds worth of errors running through the Post Office every year because of Horizon, which we’re all paying for, because the Post Office, were it not a publicly owned company, would be insolvent. It only exists by the largesse of the government funding it, so we are all paying today, every one of us, in our taxes for the errors that are still taking place in the Horizon system.”

Fujitsu still operates Horizon

Glick also said that Fujitsu is still operating the system because nobody else knows how to run Horizon. “Fujitsu is the only company that does. The Post Office has almost zero skills in operating Horizon itself because it outsourced everything. It outsourced all the skills and the knowledge and the expertise as well.

“So, this is still a live scandal in every sense of the word. For all of us in IT, we must ask the questions ‘have we really learned from this?’ Looking back now, when the flaws in Horizon became apparent, we knew what questions to ask. If you’re developing a system now like this in AI, arguably we don’t even know the questions to ask, let alone the answers. Everybody in the IT industry still needs to learn the lessons from this, because if we get a post office scandal that’s generated by AI, it could be exponentially worse.”

Getting struck off

Sir Kenneth Olisa, whose career began at IBM in the 1970s, founded and led the AIM-listed technology merchant bank Interregnum and now leads Restoration Partners, said the lack of professionalism in the IT sector was something that needs to be urgently addressed.

“To answer no difference in professional qualification and industrial qualification is if you get it wrong, you get struck off. And one of the challenges in IT, and it is an industrial problem for us, in my experience, is so few people understand what we do, how we do it, why we do it, and that’s why we aren’t challenged.

“So, in the absence of professional and engineering challenges in our sector is, I think, the underlying cause of problems here, because you just say whatever you need to say, because no one is going to push back against you, there is no accountability.

“I would also point out a statement made by one of the heads of Logica at an event I attended. He said: ‘There’s no such thing as a big IT project but only a major change management project in IT at its core.'”

Consequenses

John Carrington, whose career includes roles in the GPO, the forerunner to the Post Office, and as founding CEO of Cellnet, said: “The answer to what needs to be done to me is probably summed up in one word, which is consequences.

“The software guys who knew it was a bag of rats didn’t speak out because the consequences for them didn’t come from the profession. It came from their employer.

“In terms of developing the IT professional standards, there needs to be consequences such as being struck off. So, I think there’s a major job to be done here in our own profession, and I think the world needs to learn from ossified management structures. Which care more for form, rather than the people who work for them.”

The latest

A statutory inquiry was launched in 2020, chaired by Sir Wyn Williams, and has held extensive hearings since February 2022 across several phases, focusing on the human impact, system errors, and prosecution, with closing statements being made in December 2024.

The Post Office Horizon IT Inquiry’s final report Volume 1 was published in July 2025, and detailed the devastating human impact and failures in redress for sub-postmasters, recommending swift, fair, and prompt compensation, including for close family. It found compensation schemes have often failed victims and urged action from the government, Post Office, and Fujitsu for restorative justice.

Volume 2 is expected to be published the summer of 2026, focusing on systemic failures, the role of senior leadership at the Post Office and Fujitsu, the legal profession, and the culture that allowed the injustice to persist. It will also cover the human impact and further recommendations on redress and overall recommendations.

Criminal Investigation

Also in 2020, a criminal investigation was launched by the Met Police called Operation Olympos into allegations the Post office knowingly used discrepancies recorded on the Horizon system to take action against sub-postmasters it accused of theft and false accounting.

The investigation is ongoing but to date nobody has been charged. The Met states that between 2000 and 2017 the Post Office initiated 900 private prosecutions against sub-postmasters, 736 of whom were prosecuted. Others faced a combination of civil claims and termination of contracts.

This week, Karl Flinders, a journalist for Computer Weekly, who has written hundreds of stories on the Horizon scandal and joined AIT’s Forum online, announced that Fujitsu’s CEO in Europe, Paul Patterson, was stepping down.

“He will avoid having to lead the company during the huge backlash which is likely to come when the Post Office public inquiry lays bare Fujitsu’s share of the blame for the suffering of subpostmasters caused as a result of the company’s flawed Horizon software.”

Horizon: Lessons Learnt? Highlights from Archives of IT’s 2026 Forum