In 2022, journalist Alex Renton told the story of sexual abuse and cover up in Britain’s elite schools, including his own. After the Radio 4 series aired, his inbox exploded; with people sharing their personal accounts of abuse.

Last spring, and anothr email. This one came with an attachment: a scanned copy of a membership list for a pro-paedophile campaign group active in the 1970s and 80s. The group's name was the Paedophile Information Exchange, or PIE for short.

The PIE List sets Alex - himself a survivor of child sexual abuse - on a dizzying journey into the group’s dark history.

As he digs further, a source gets in touch; could Alex travel to meet him? During that meeting he hands him other secret documents, which build a picture of the criminal activities of some of PIE’s members: teachers, clergymen, social workers, government advisors.

Alex begins to wonder: where are all those hundreds of PIE members now? Are children still at risk?

Presenter: Alex Renton Producer: Caitlin Smith Researchers: Claire Harris and Marisha Currie Executive producers: Gail Champion and Gillian Wheelan Story Consultants: Jack Kibble White and Kirsty Williams Written by Alex Renton, Caitlin Smith, Jack Kibble White and Kirsty Williams Sound designer: Jon Nicholls Theme tune composed by Jeremy Warmsley Commissioning executive: Tracy Williams Commissioner: Dan Clarke

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

Alex Renton has letters and documentation passed to him by a secret source. He tries to track down a former member of the defunct pro-paedophile group, the Paedophile Information Exchange, or PIE.

He delves into the group's origins and discovers that figures within PIE didn’t just groom the people around them, they attempted to groom whole movements.

The group formed in 1974; a time when marginalised groups were campaigning for equality and legal change. PIE took heed, that’s what they wanted.

So they aligned themselves with minority rights groups. And, these groups, whose ethos was to be open hearted, trusting - bought into it. They were fooled.

Alex Renton speaks with men who were part of gay youth groups in the 1970s that were targeted and manipulated by PIE and its members.

And he makes a breakthrough with the membership list.

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

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