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 17, Nick explores how senior Post Office lawyers and managers reacted in 2013 to the biggest challenge to the Horizon system yet. After MPs forced an independent investigation which identified bugs in Horizon, the Post Office publicly backed their computer system and reaffirmed their faith in the prosecutions they had conducted. But behind the scenes, all hell was breaking loose.

Presenter: Nick Wallis Producer: Robert Nicholson Sound Design and Mixing: Arlie Adlington Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

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 Wallis Producer: Robert Nicholson Sound Design and Mixing: Arlie Adlington Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

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 15, we hear how the Post Office ruined the life of Lee Castleton, a Sub Postmaster based in Bridlington who was taken to court over debts he says came from the Horizon computer system. New evidence reveals that the Post Office failed to investigate Lee's claims of computer errors in depth before taking him to court, and shows that evidence that may have cast doubt on Horizon was known about but not provided at the trial.

Presenter: Nick Wallis Producer: Robert Nicholson Sound Design and Mixing: Arlie Adlington Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

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 14, we hear how the Post Office disregarded red flags about Horizon when it rolled the system out, and how flawed and incomplete prosecution policies set the stage for the mass prosecution of many innocent Sub Postmasters.

Presenter: Nick Wallis Producer: Robert Nicholson Sound Design and Mixing: Arlie Adlington Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

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.

Presenter: Nick Wallis Producer: Robert Nicholson Sound Design and Mixing: Arlie Adlington Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

In this bonus episode of The Great Post Office Trial, hear Nick Wallis' full interview with Post Office CEO Nick Read - the first Post Office CEO to ever give an interview about the scandal.

Nick Wallis has been investigating the Post Office Horizon scandal for more than a decade, revealing the true story of the Post Office's persecution of its own Sub Postmasters.

A long campaign for justice has forced the launching of a wide ranging public inquiry, which started hearing evidence last year. The Post Office and the government have also agreed to run three separate compensation schemes to try and make things right.

The inquiry is forcing extraordinary evidence to light. It implicates senior staff in stunning cultural failings. But even as this picture emerges, campaigners and politicians following the scandal are ringing alarm bells about how the Post Office is behaving now.

Key people who are accused of covering up the scandal are still in their jobs, even as the Post Office claims to have turned over a new leaf. Post Office bosses recently generated fresh outrage by awarding themselves generous bonuses for helping the inquiry complete its work, despite the fact that the inquiry has only just started. Post Office CEO Nick Read has apologised and returned the bonus, after the inquiry rebuked the Post Office directly.

And, as Nick Wallis explores the Sub Postmasters' fight for fair compensation, he discovers that many feel the Post Office is treating them now just as they have treated them throughout the worst of the scandal.

In a new edition of The Great Post Office Trial, hearing from people at the heart of a fresh wave of revelations, Nick discovers a shocking truth - the scandal, even as it is being investigated by a public inquiry, is far from over.

Presenter: Nick Wallis Producer: Robert Nicholson Executive Producer: Will Yates Sound Designer: Emma Barnaby

A Whistledown production for BBC Radio 4

In a follow up to the ten-part series The Great Post Office Trial, Nick Wallis explores how campaigners for justice around the Post Office scandal have been continuing the fight, and reveals startling new details on the story which have emerged in court.

Since the original series aired, the government has officially launched an inquiry, chaired by Sir Wyn Williams. After controversy over its initially limited powers and scope, it's been widened and given statutory powers. Some Sub Postmasters are also seeking further legal redress, and attempting to pressure the government to cover the Sub Postmasters' costs from the initial trial. The minister responsibe, Paul Scully, sits down for his first interview on the subject with Nick Wallis.

As the potential cases of miscarriage of justice work their way through the Court of Appeal, Nick discovers revelatory new documents which cast fresh light on what was going on inside the Post Office as the scandal unfolded.

And we hear newly emerged stories of more Sub Postmasters affected, as the full scale of the story becomes clear.

Presenter: Nick Wallis Producer: Robert Nicholson Executive Producer: Will Yates

A Whistledown production for BBC Radio 4

After the introduction of a new computer system in the early 2000s, the Post Office began using its data to accuse sub-postmasters of falsifying accounts and stealing money. Many were fired and financially ruined; others were prosecuted and even put behind bars.

In this ten-part series, journalist Nick Wallis, gets right to the heart of the story, as he talks to those whose lives were shattered and follows the twists and turns of a David and Goliath battle as the sub-postmasters tried to fight back.

In the series finale, the sub-postmasters’ litigation comes to an end - but not everyone is happy. Nick asks what should happen next for the Post Office, and there’s a breathtaking revelation from the Criminal Cases Review Commission.

Presenter: Nick Wallis Producer: Robert Nicholson Executive Producer: David Prest With Sound Design from Emma Barnaby and Story Editing from Alexis Hood. A Whistledown production for BBC Radio 4

After the introduction of a new computer system in the early 2000s, the Post Office began using its data to accuse sub-postmasters of falsifying accounts and stealing money. Many were fired and financially ruined; others were prosecuted and even put behind bars.

In this ten-part series, journalist Nick Wallis, gets right to the heart of the story, as he talks to those whose lives were shattered and follows the twists and turns of a David and Goliath battle as the sub-postmasters tried to fight back.

Today, Alan Bates and the sub-postmasters reach the High Court, and the Post Office’s secrets start to tumble out one by one.

Presenter: Nick Wallis Producer: Robert Nicholson Executive Producer: David Prest With Sound Design from Emma Barnaby and Story Editing from Alexis Hood. A Whistledown production for BBC Radio 4

After the introduction of a new computer system in the early 2000s, the Post Office began using its data to accuse sub-postmasters of falsifying accounts and stealing money. Many were fired and financially ruined; others were prosecuted and even put behind bars.

In this ten-part series, journalist Nick Wallis, gets right to the heart of the story, as he talks to those whose lives were shattered and follows the twists and turns of a David and Goliath battle as the sub-postmasters tried to fight back.

Today, the sub-postmasters have hit rock bottom. Working with the Post Office has failed and their last hope is a long shot lawsuit. But Nick manages to get hold of some crucial documents and a whistleblower which might make all the difference.

Presenter: Nick Wallis Producer: Robert Nicholson Executive Producer: David Prest With Sound Design from Emma Barnaby and Story Editing from Alexis Hood. A Whistledown production for BBC Radio 4