The 700-plus sub-postmasters wrongly accused of theft and fraud in what may be the UK’s greatest miscarriage of justice faced four distinct barriers which explain why the scandal took years to come to light, new research from the University of Bath’s School of Management shows.

Researchers analysed hundreds of transcripts from the ongoing public inquiry into the scandal and conducted interviews with sub-postmasters across the UK in an effort to understand why so few victims had spoken out. The ongoing study, funded by a grant from the British Academy and Leverhulme Trust and featured in The Conversation, has identified three major issues with the Post Office and its management, and one from the sub-postmasters’ own local communities.

• Within the Post Office, sub-postmasters who raised questions about the Horizon IT accounting system were effectively isolated by managers who claimed they were the only ones facing such problems, creating a culture of silence, self-doubt and shame.

• Further, they were denied access to the technology and data to defend themselves, creating the belief that fighting back would be futile.

• This sense of hopelessness was in turn exacerbated by the Post Office’s longstanding reputation as a highly respected organisation and a culture among managers which did not welcome criticism or questions.

• Outside the organisation, the study identified that victims were stigmatized by their own local community, making them feel ashamed and feeling that nobody would believe their story against the weight of the trusted Post Office brand.

Dr Grace Augustine, of the University’s School of Management, said she hoped that understanding the barriers would help people understand why miscarriages of justice often take a long time to surface.

“When such injustices come to light, we often hear people ask, why didn’t they tell someone? There are numerous legitimate reasons people don’t speak up, especially when they are intentionally isolated, experience self-doubt, shame, and do not have the information to prove their word against a powerful perpetrator,” Dr Augustine said.

The study notes that sub-postmasters were highly vetted individuals, subjected to background and character checks. Dr Augustine said the notion that such a high percentage of them were criminals was highly unlikely and that this should have rung alarm bells inside the Post Office’s management team.

Instead, they were disbelieved throughout. As Jo Hamilton, a sub-postmaster from a village in Hampshire, told the public inquiry: “I began to feel like I was going mad and that it was entirely my fault … When he said I was the only one, that’s how I did feel … I thought: Oh God, I must be – you know, I just thought it was me.”

Dr Augustine said: “Post Office employees falsely believed that their technological systems were infallible and dug their hells in at any opportunity to recognise this injustice for what it was. They were quick to believe the computer and blame the user. At the end of the day, this is not a scandal about technological failing, it is a scandal about the gross failure of management,” she said.

She warned that such ‘automation bias’, underpinned by an unfettered belief in the accuracy of technology, is having serious consequences with the advance in artificial intelligence.

“For example, a recent story in the New Yorker highlighted how police departments in the US are increasingly relying on AI facial-recognition technology to identify suspects from large databases. Arrests have been made based on this evidence alone and the practice has gone largely unchallenged, even though there are now multiple cases of false arrests made solely on these algorithms – even some that have turned up suspects living in completely different US states. We struggle to challenge the authority of technology, and the risk of this will be even more pronounced if we cannot overcome this bias,” she said.

Dr Augustine studies how people fight back against injustices at work, and noted that in this case, collective effort was central to making any progress to overcome these barriers. The project From Paralysis to Publicization: How Victims of the Post Office Horizon Scandal Experienced and Confronted Organizational Harm is ongoing and welcomes input from anyone affected by this scandal.