Chris Mullin discovers what changed as a result of the Birmingham Six case, which he investigated, and asks whether a similar miscarriage of justice could be repeated today.

The author Robert Harris, commenting on the release of the Birmingham Six in 1991, wrote that "whoever placed the bombs in Birmingham also placed a bomb under the British legal establishment". The overturning of the convictions caused shock and outrage and led to major reforms in police investigations, criminal prosecutions, and assessments of possible miscarriages of justice.

It's now over 40 years since the trial of the six innocent men convicted of the Birmingham pub bombings. Their release 17 years later, amid much official breast-beating, led to the setting up of a Royal Commission and, in due course, to changes in criminal procedure with a view to ensuring that mistakes of this sort could never happen again. In particular it led to the creation of the Criminal Cases Review Commission which is empowered to investigate alleged miscarriages of justice and to refer doubtful cases back to the Court of Appeal. Around 400 convictions have been quashed as a result of references by the CCRC.

This programme examines what changed as a result of the Birmingham Six case and whether a similar miscarriage of justice could be repeated today. Presenter Chris Mullin investigated the case as a journalist before he became a Labour MP and helped to establish the innocence of the Six. Contributors include former Director of Public Prosecutions Sir Keir Starmer, former Attorney General Dominic Grieve, and current Head of the National Police Chiefs Council, Sara Thornton.

Presenter: Chris Mullin is the author of 'Error of Judgement - the truth about the Birmingham Bombings.' He also helped make four World in Action documentaries on the case. He is a former chairman of the House of Commons Home Affairs Committee.

Producer: Jonathan Brunert.