News Summary

• A Horizon system ‘operational defect’ could be at the root of unexplained discrepancies, according to a forensic investigator.
• Ron Warmington at forensic investigation firm Second Sight has written to the Post Office scandal public inquiry warning that current subpostmasters might not be aware of the issue.
• The defect was brought to the attention of Computer Weekly by former subpostmaster Denis O’Donnell, who ran a branch in Prestatyn, Wales, for decades.
• The revelation comes at a time when Post Office is experiencing large volumes of unexplained accounting shortfalls and using millions of pounds of taxpayer money to cover them.