Tales of stars having sex on work premises, strong 'herbal smells' wafting down corridors and presenters appearing in front of the camera 'stoned out of their minds', are all set to feature in a revealing documentary about BBC Television Centre.

According to a new BBC4 documentary, 'Lights! Camera! Action! Tales of Television Centre' – some Play School presenters even went in front of the camera after smoking "the biggest joint you've ever seen".

Presenter Johnny Ball told the documentary team that two of his co-stars shot a nativity scene for children's TV show Play School while stoned.

Ball said, 'There was Rick Jones, Lionel Morton and myself. They got stoned on the biggest joint you've ever seen - in the studio. We were in silhouette as the three shepherds with our crooks. Lionel purposely held his crook so the crook didn't show.

"They were absolutely stoned out of their minds. So when we recorded, who cocked his lines up? Me."

The documentary also claims Sir David Attenborough even had to complain about the smell of drugs in the corridors of Television Centre after pop stars smoked before performing.

Joan Bakewell said there were complaints about musicians who "didn't smoke ordinary cigarettes" and said Sir David - then BBC2 controller - complained about the "herbal smell" in the corridor.

The show also reveals that Barry Norman was nearly sacked after an executive at the BBC thought he wore a wig on screen.

Norman said, "I wasn't actually wearing a wig, I was just having a bad hair day."

The documentary features interviews with dozens of BBC staff including Brian Blessed and Sir Terry Wogan.