The Zero Imperative (home video)

 was the first BBV Productions video-released film to feature Caroline John reprising her role as Elizabeth Shaw. This was also the first story to introduce PROBE – the Preternatural Research Bureau which would feature in the four BBV Productions PROBE films.

Synopsis
Former UNIT luminary Liz Shaw and her assistant Lou Bayliss are investigating a series of bizarre murders, all committed near a soon-to-be-closed psychiatric hospital.

When the hospital is unexpectedly reprieved by rich industrialist Peter Russell, events seem to move out of Liz's control. Are the incumbent director of the clinic, Doctor Dove and his predecessor, Doctor O'Kane, harbouring the killer? What is the centuries-old horror hidden in the grounds?

And what exactly is the secret of room zero?

Plot
to be added

Cast

 * Liz Shaw - Caroline John
 * Dr. Jeremiah O'Kane - Jon Pertwee
 * Dr. Colin Dove - Sylvester McCoy
 * Dr. Peter Russell - Colin Baker
 * Lou Bayliss - Linda Lusardi
 * Patient Zero (David O'Kane) - David Terence
 * Dr. William Bruffin - Mark Gatiss
 * Dr. Beatrice Hearst - Nicola Fulljames
 * Patricia Haggard - Louise Jameson
 * Dr. Gilchrist - Patricia Merrick
 * Cummings - Jonathan Rigby
 * P.R.O. - Sophie Aldred
 * Orderly - Simon Messingham
 * Orderly - Alexander Kirk
 * Daniel - Bill Baggs
 * Boy's Voice - Daniel Mills
 * Patient One - Peter Davison

Production crew

 * Executive producer - Andy Grant
 * Original Music - Mark Ayres
 * Cinematography - Dick Kursa
 * Film Editing - Michael Duxbury
 * Art Direction - David Rowston
 * Makeup artist - Sarah Dickinson
 * Assistant directors - Patricia Merrick, David Rowston, Edward Salt
 * Gaffer - David Hilton

Story notes

 * Gary Gillatt created the Nightshade video covers which appear on Jeremiah O'Kane shelves.
 * This film is the debut of the Preternatural Research Bureau (PROBE) and the return of Caroline John as Liz Shaw, a character last seen on television in TV: Inferno in 1970 (discounting a psychic projection of Shaw played by John that appeared in 1983's The Five Doctors).
 * Several cast members previous portrayed (other) roles in Doctor Who: Jon Pertwee (Third Doctor who acted along side Caroline John); Colin Baker (Sixth Doctor); Sylvester McCoy (Seventh Doctor); Sophie Aldred (Ace); Louise Jameson (Leela); and Peter Davison (Fifth Doctor). Any actor to formerly play the Doctor plays a doctor in the film.
 * Simon Messingham also wrote: PROSE: Strange England PROSE: The Face-Eater, The Infinity Race, PROSE: Tomb of Valdemar and The Indestructible Man.
 * This is the first of four films featuring the PROBE organisation. It pre-dates Torchwood as the first ongoing spin-off of the Doctor Who universe.
 * This story marks the first time Pertwee, Aldred, Jameson and Davison have played more than one character in the Doctor Who universe. It is not the first time for Baker and McCoy, however: Baker played Maxil in TV: Arc of Infinity and McCoy briefly played the Sixth Doctor in TV: Time and the Rani.

Myths
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Filming Locations
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Discontinuity, Plot Holes, Errors
to be added

Continuity

 * Liz Shaw last appeared on-screen in TV: Inferno, apart from a brief appearance as a psychic projection in TV: The Five Doctors. In spin-off media, she appeared with the Third Doctor several times chronologically afterward (PROSE: The Wages of Sin, and The Devil Goblins from Neptune). Later accounts vary, as one said she died in 2003 while on the Moon (PROSE: Eternity Weeps), but according to Colonel Tia Karim she was still alive and on the Moon as of the Doctor's staged funeral in 2010. (TV: Death of the Doctor)

DVD, video, and Other releases
to be added