Japanese firm Fujitsu s faulty software was behind more than 900 subpostmasters being wrongly prosecuted after shortfalls were incorrectly reported on their accounts.
Scandal-hit Horizon system may operate in Post Office branches for another five years lbc.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from lbc.co.uk Daily Mail and Mail on Sunday newspapers.
Mike Young accused former Post Office boss Paula Vennells of trying to put the blame for the wrongful convictions of subpostmasters over missing money on the faulty Horizon IT system.
The huge police inquiry into the Post Office scandal will use 80 detectives and be on the scale of a major murder or terrorism investigation , it has been reported.
In an emotional testimony, Ms Vennells said she "loved the Post Office" and worked "as hard as I possibly could to deliver the best Post Office for the UK".