Horizon Post Office scandal: Yorkshire engineer who installed Horizon IT system describes 'anger' and 'sadness'

Graham Askham was part of a team of electrical engineers who travelled the length and breadth of the country installing the new system, which is at the heart of possibly the biggest miscarriage of justice in national history.

Mr Askham, from Sheffield, said he and his colleagues were unaware at the time of any faults with the system and never heard any complaints from the sub-postmasters they met during the course of their work.