The Post Office scandal is one of the UK's most widespread miscarriages of justice, with hundreds of people wrongfully convicted of theft or false accounting. In most of these cases, the Post Office was the investigator, prosecutor and the alleged victim.

Did Post Office lawyers act unethically by failing to disclose evidence that might have helped the people they were prosecuting? Might they face criminal proceedings for attempting to pervert the course of justice?

The Post Office no longer brings private prosecutions in cases such as this. But should we still be allowing anyone apart from a public prosecutor to bring criminal proceedings in the name of the state?

Presenter: Joshua Rozenberg Producers: Arlene Gregorius and Diane Richardson Researcher: Marianna Brain Editor: Clare Fordham Production coordinator: Maria Ogundele Sound engineer: Neil Churchill