The Post Office Horizon Scandal has been called the widest miscarriage of justice in modern British history, with the number of former Sub Postmasters whose convictions have been overturned now over 60. Those who suffered prosecution or financial ruin due to errors on the Post Office's Horizon computer system want answers. How could this have happened? Who is responsible?

Continuing the series that has helped expose the scandal since 2020, Nick Wallis draws on interviews, documents and the extraordinary revelations spilling out of the ongoing public inquiry. For the first time, the public is getting real insight into what was really going on inside the Post Office.

In Episode 16, we hear how newly revealed documents show that the Post Office rejected even internal calls for an independent investigation of Horizon. They instead commissioned a deliberately one sided internal report which never even considered evidence of errors. This report was nevertheless used to justify dismissing Sub Postmasters' concerns and maintaining an aggressive prosecution strategy.

Presenter: Nick WallisProducer: Robert NicholsonSound Design and Mixing: Arlie AdlingtonExecutive Producer: Will Yates

A Whistledown production for BBC Radio 4