UK police have opened a fraud investigation into Britain’s Post Office over a miscarriage of justice that saw hundreds of postmasters wrongfully accused of stealing money when a faulty computer system was to blame.

The Metropolitan Police force said late Friday that it is investigating “potential fraud offences arising out of these prosecutions,” relating to money the Post Office received “as a result of prosecutions or civil actions” against accused postal workers.

Police also are investigating potential offences of perjury and perverting the course of justice over investigations and prosecutions carried out by the Post Office.

Between 1999 and 2015, more than 700 post office branch managers were accused of theft or fraud because computers wrongly showed that money was missing. Many were financially ruined after being forced to pay large sums to the company, and some were convicted and sent to prison. Several killed themselves.

The real culprit was a defective computer accounting system called Horizon, supplied by the Japanese technology firm Fujitsu, that was installed in local Post Office branches in 1999.

The Post Office maintained for years that data from Horizon was reliable and accused branch managers of dishonesty when the system showed money was missing.

After years of campaigning by victims and their lawyers, the Court of Appeal quashed 39 of the convictions in 2021. A judge said the Post Office “knew there were serious issues about the reliability” of Horizon and had committed “egregious” failures of investigation and disclosure.

Police have opened a fraud investigation into Britain’s Post Office over a miscarriage of justice that saw hundreds of postmasters wrongfully accused of stealing money. Photo / AP

A total of 93 of the postal workers have now had their convictions overturned, according to the Post Office. But many others have yet to be exonerated, and only 30 have agreed to “full and final” compensation payments. A public inquiry into the scandal has been under way since 2022.

So far, no one from the publicly owned Post Office or other companies involved has been arrested or faced criminal charges.

Lee Castleton, a former branch manager who went bankrupt after being pursued by the Post Office for missing funds, said his family was ostracised in their hometown of Bridlington in northern England. He said his daughter was bullied because people thought “her father was a thief, and he’d take money from old people”.

He said victims wanted those responsible to be named.

“It’s about accountability,” Castleton told Times Radio on Saturday. “Let’s see who made those decisions and made this happen.”

The long-simmering scandal stirred new outrage with the broadcast this week of a TV docudrama, Mr. Bates vs the Post Office. It charted a two-decade battle by branch manager Alan Bates, played by Toby Jones, to expose the truth and clear the wronged postal workers.