Presenters from the hit BBC children's show Play School often went on air stoned a new BBC documentary has revealed.
Rick Jones and Lionel Morton were able to go in front of the camera stoned after smoking "the biggest joint you've ever seen" because bosses at the BBC turned a blind eye in the 70's, Johnny Ball claims in the tell-all documentary.
The disclosures are made in Tales of Television Centre due, to air on May 17 on BBC Four, which uncovers just how drugs and sex were able to spill onto the nativity scene.
Ex-presenter Johnny 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."
During the programme, it is also revealed that at one point Sir David Attenborough even complained about corridors at the TV Centre reeked of cannabis and the fact that people were "bonking all over the place".
Meanwhile, former presenter Joan Bakewell says that there were often complaints about visiting pop groups who would often smoke wacky baccy on the premises.
She said: "Of course they smoked and they didn't smoke ordinary cigarettes."
The show, which features interviews with dozens of BBC staff and small-screen stars on-screen including Sir Terry Wogan and Brian Blessed also uncovers the sex and drug lifestyle on behind the closed doors of the stars' dressing rooms.
Former Doctor Who actress Katy Manning, who played Jo Grant, said: "People were bonking all over the BBC. Everybody was doing it on the premises."