Post Office defends software after probe reveals bugs

The Post Office has been forced to defend its Horizon accounting software, following an independent investigation into whether bugs led to staff being wrongly accused – and even jailed – for false accounting.

Around 60 sub-postmasters submitted claims to investigators that they were wrongly accused of cooking the books, after Horizon inaccurately calculated shortfalls in their branches. The system is used by around 68,000 people across 11,500 branches and processes six million transactions a day.

Due to contractual obligations to make up for those shortfalls, staff have had to repay thousands of pounds themselves and a number were jailed for false accounting. North East Hampshire MP James Arbuthnot called for an investigation into Horizon after one sub-postmaster, Jo Hamilton, said she had been unfairly sacked from her branch.

We want justice for what has been awful – some people have gone to prison

A preliminary investigation commissioned by the Post Office and conducted by fraud investigators Second Sight has found the Horizon system worked properly – but the report noted that several cases were highly complex and that further investigation was needed.

Confusingly, the Post Office admitted during the investigation that it had found “defects” with Horizon in the past, but insisted this wasn’t evidence of a wider problem. The report, seen by PC Pro, noted two instances during the last two years where the Post Office found Horizon falsely calculated shortfalls or surpluses ranging from hundreds of pounds to thousands.

Further probe required

Responding to the report, the Post Office insisted Horizon worked “effectively”, though it admitted it needed to better train its staff in how to use the system.

“The report confirms that no system-wide problems have been found in relation to the Horizon software, but suggests that the Post Office should examine its support and training processes for sub-postmasters,” said chief executive Paula Vennelis.

But the report also slammed the Post Office for failing to identify the root causes of the accounting flaws during its initial investigation.

“We can’t help concluding that had Post Office Limited investigated more of the “mysterious shortages” and problems

reported to it, with the thoroughness that it has investigated those reported to it by Second Sight, POL would have been in a much better position to resolve the matters raised, and would also have benefited from process improvements,” it said.

Second Sight’s interim report covers just four out of the 47 complaints made by sub-postmasters, and investigations are still underway. According to the BBC, the affected sub-postmasters have all expressed an interest in suing the Post Office over the repayments and prosecutions.

“We want justice for what has been awful. Some people have gone to prison,” Jo Hamilton told the BBC.

The trade union for sub-postmasters, the NFSP, said it had “confidence” in Horizon. “While we have never been presented with clear evidence that the Horizon system had failed to meet its primary purpose, we are nonetheless reassured that the system has been found to be robust in an independent survey, and we continue to have confidence in it,” said general secretary George Thompson.