Ghostwatch was a controversial British horror-mockumentary television programme which was aired on the BBC on October 31 (Halloween), 1992. It was written by Stephen Volk and produced by Ruth Baumgarten .

The 90-minute film was a horror story shot in a documentary style and appeared as part of BBC Drama's Screen One series. It involved BBC reporters performing a live, on-air investigation of a house in North London at which poltergeist activity was taking place. Through revealing footage and interviews with neighbours and the family living there, they discovered the existence of a malevolent ghost named "Pipes", from his habit of knocking on the house's plumbing. As the programme went on, the manifestations of "Pipes" became more bold and terrifying, until, at the end, the frightened reporters realised that the programme itself was acting as a sort of "national séance" through which "Pipes" was gaining horrific power. Finally, the spirit escaped, and haunted the BBC studios themselves, possessing the reporters present as a prelude to its unleashing on the world.

In truth, the story, though based on the tale of the Enfield Poltergeist, was filmed weeks before and was complete fiction. However, the presentation contained realistic elements which suggested to a casual viewer that it was an actual documentary. A phone number was shown on the screen so that viewers could "call in" and discuss ghostly phenomena (the number was actually connected to a local society for psychic research, who explained that the show was fictional). The set and filming methods, including shaky hand-held video cameras, lent to a documentary feel. Most convincing of all was the use of actual BBC news personalities playing themselves. Sarah Greene and Craig Charles were the reporters on the scene at the house, while Mike Smith and Michael Parkinson narrated from the studio.

The film caused an immediate, minor panic in Britain, similar to that created by the airing of Orson Welles's version of The War of the Worlds, as many assumed the events to be true. The BBC was besieged with phone calls from irate and frightened viewers, and British tabloids and other newspapers criticised the BBC the next day for the disturbing nature of some scenes, such as Greene's final scene where she is locked in a cellar with the howling ghost, and Parkinson's eerie possession scene. Two children were reportedly diagnosed with posttraumatic stress disorder, supposedly due to the nature of the programme, and one tabloid insinuated that it had caused a teenager to commit suicide. The film's producers answered the controversy by saying that it aired during a drama slot, that it was recognizable as fiction to a vast majority, and that running disclaimers or other announcements during the programme would have ruined its effectiveness. Nonetheless, the BBC has refused to ever show the programme again since that time.