Alex Renton tries to find out more about the notes scribbled in the margins of the PIE membership list. It looks like they were written by police, who were going door to door visiting the members listed in the document. But this active investigation appears to stop suddenly in 1985. Why?

Alex starts piecing together the police investigation into the Paedophile Information Exchange.

He discovers the PIE List was seized by the Metropolitan Police in the late seventies and passed to a unit called the Obscene Publications Branch or as it was known internally 'the Dirty Squad'.

Presenter: Alex Renton
Producer: Caitlin Smith
Executive Producers: Gail Champion and Gillian Wheelan
Story Consultants: Jack Kibble-White and Kirsty Williams
Sound design: Jon Nicholls
Theme Tune: Jeremy Warmsley

Actor readings: David Hounslow and Samuel James.

Archive: Newsnight, 1983 BBC; Mary Whitehouse film archive, Huntly Film Archive 1964; Mastermind 1979 , BBC.

Details of organisations offering information and support for victims of child sexual abuse are available at bbc.co.uk/actionline