The Post Office scandal shows the perils of putting our faith in IT

If the Post Office scandal teaches us one thing, it’s that the computer isn’t always right, says Chris Blackhurst. In a world where data systems influence so many crucial aspects of our daily lives, the potential for another Horizon-type scandal is clear and present

Former subpostmistress Kathleen Crane (centre) outside the Royal Courts of Justice in London after judges quashed her fraud conviction (PA)

What was telling in the cases of the Post Office operators suspected of fraud was the lack of corroborative evidence.

They were supposed to have stolen thousands of pounds, yet there was precious sign of the money being spent on anything. There were no flash sports cars, speedboats, foreign villas or exotic holidays; no debts were paid off, and no cosmetic surgery occurred. If one subpostmaster had been careful and discreet, then that was possible, but 700 of them? It didn’t add up.

According to an expert drafted in by the Post Office to examine the computer data suggesting fraud or false accounting on a mammoth scale, it was this that first alerted them – the signal that something was odd. They were asked if the evidence against the subpostmasters was robust enough to be used in a court of law, in civil and criminal proceedings.