Independent forensic computer experts Second Sight has found 12,000 communication failures a year in the Post Office software programme Horizon. 

The accountancy programme, for which over a decade has reported unexplained losses and accounting errors, has seen subpostmasters suffer financial penalties for faults they believe are within the software.

MPs on the Business, Innovation and Skills Select Committee took evidence about the mediation scheme established by the Post Office to resolve these cases. Ian Henderson, forensic computing expert at Second Sight, said: “Although Horizon had processes in place to deal with communication failures, in a few cases there had been problems.”

Henderson added that Second Sight had not received emails and data relating to the suspense account that it had requested. He said: “These factors have severely constrained the organisation’s ability to carry out an independent investigation.”

Paula Vennells, Post Office chief executive, stressed that the Post Office had shared all the information it could. Any delays were because “each case was properly investigated,” she added.

Labour MP Paul Bloomfield noted that out of the 150 people who had applied to the mediation scheme, 110 had not had their cases resolved. 

Alan Bates, chairman for justice for sub postmaster’s alliance (JFSA), said the time to process each claim had taken “far longer” than anticipated, adding that each organisation including JFSA, Post Office and Second Sight had become more “partisan” as the scheme had progressed.

Conservative MP Brian Binley questioned whether the support and training for workers had been sufficiently robust throughout the Horizon programme. Mark Baker, national branch secretary, Postmasters Branch, Communication Workers Union, added that the current training packaged was “rubbish,” noting the amount of misinformation within it.