Ghostwatch in a Cave at Halloween

The team wanted to push the boundaries of reality even further. They didn't want it fronted by conventional actors - they wanted familiar and friendly TV personalities to bring the story to life.

Michael Parkinson, one of the BBC's most trusted faces, was asked to present it. Alongside him was popular children's television presenter Sarah Greene, together with her husband, TV and radio host Mike Smith - a fact Volk calls a "happy accident".

"It was offered to Sarah [initially] and Mike - I think - happened to read it over her shoulder and said "can I be in it [too]?'

"I quickly thought, 'this is a real bonus'," says Volk.

It was groundbreaking television in many ways - from the infra-red, heat-seeking camera used to "spot" ghostly activity to the pixellation of an interviewee's face.

They also used videotape, instead of the typical 16mm film, to make it look more homemade.

Though the production team wanted it to look realistic, shortly before its transmission the programme featured on the cover of the Radio Times, inside which it was explained it was a drama.

But not everyone read the Radio Times. And when Ghostwatch aired at 21:25 GMT, there were consequences the corporation had not foreseen.

Watch the classic 1992 film in a dark cave beneath the streets of Nottingham at Halloween! We'll be joined by the director of Ghostwatch, Lesley Manning who will be in conversation with Will from Boo The Bad Guy. Lesley will be meeting fans, taking selfies and signing autographs.