The treatment of one former Post Office branch owner by the organisation was likened on Friday to a “mafia hit”.
Michael Rudkin, from Leicestershire, was shown in the ITV drama Mr Bates vs The Post Office visiting the headquarters of Fujitsu, where an employee showed it was possible for IT engineers to remotely access the Horizon system used by sub-postmasters.
That undermined the central claim of the Post Office, that only the sub-postmasters could access the system and so they were solely responsible for any shortfalls.
Mr Rudkin's wife Susan was one of hundreds of branch workers wrongly convicted of stealing money, while he lost his job and union position.
Lord Arbuthnot, who as an MP took up the sub-postmasters’ case, told Times Radio: “The day after he goes to Fujitsu and discovers all of these shocking things, he is then raided and removed from his post as sub-postmaster.
“If that was an act of revenge or silencing, it's very difficult to see that this was not a mafia hit.”
His comments came after Post Office investigator Stephen Bradshaw denied at an ongoing inquiry that he behaved like a “mafia gangster” in helping to falsely convict nine sub-postmasters.
The inquiry began in 2021 following a High Court ruling that Horizon was riddled with bugs and errors. James Arbuthnot and a handful of other MPs had long been warning about a possible miscarriage of justice.
The Government rushed into action after the ITV programme was broadcast over New Year, vowing new legislation to issue a blanket exoneration of sub-postmasters who were wrongly prosecuted and to pay out quicker compensation.
The chief executives of Post Office and Fujitsu are set to be questioned by MPs over the scandal next week.
Lord Arbuthnot said: "I believe that Fujitsu pays a large proportion of the blame for this, and needs to bear a large proportion of the cost of redress for the sub-postmasters."
