UK Post Office Horizon scandal
Around 900 sub-postmasters were wrongfully prosecuted (roughly 700 convicted) for theft or false accounting based on faulty data; the scandal has been linked to bankruptcies, imprisonments, and at least several suicides, and is described as one of the UK's worst miscarriages of justice.
The damage was public. The root cause was preventable.
Around 900 sub-postmasters were wrongfully prosecuted (roughly 700 convicted) for theft or false accounting based on faulty data; the scandal has been linked to bankruptcies, imprisonments, and at least several suicides, and is described as one of the UK's worst miscarriages of justice.
What the software actually got wrong
The Horizon accounting software, built by Fujitsu, contained bugs that created phantom cash shortfalls in branch accounts; the Post Office denied the software could be at fault and prosecuted postmasters instead, a position only reversed after a 2019 High Court ruling.
The Horizon accounting software, built by Fujitsu, contained bugs...
The Horizon accounting software, built by Fujitsu, contained bugs that created phantom cash shortfalls in branch accounts
Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.
The Post Office denied the software could be at...
the Post Office denied the software could be at fault and prosecuted postmasters instead, a position only reversed after a 2019 High Court ruling
Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.
Beyond code coverage and "shall" testing
Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.
Surfaces this before code exists
Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.
Connects the failure mode to the hazard
Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.
Find the overlooked root causes before they ship.
Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.