4T. Doctor Who - The Invisible Enemy

Season Fifteen

Script Editor: Robert Holmes; Writers: Bob Baker and Dave Martin; Produced by: Graham Williams; Director: Derrick Goodwin; Designer: Barry Newbery; Incidental Music: Dudley Simpson;

A spacecraft en route to the Titan base is infected by a virus, and the same virus - the Swarm - also attacks the TARDIS. The Doctor is infected by the Nucleus of the Swarm. Landing at the Titan Base the Doctor and Leela are threatened by the crew. The Doctor and Leela manage to get away to a hospital for the Doctor - the Bi-Al Foundation.

Professor Marius is able to clone the Doctor and Leela, minaturise them, and inject them into the real Doctor. The hope is that they will be able to find the infection and destroy it.

The Swarm nucleus manages to get out and is enlarged to human size. It arranges for transport back to the Titan base where breeding tanks have been prepared for it.

The now cured Doctor, along with the help of Professor Marius's mobile computer K-9, manages to set a trap which will blow up the breeding tanks. As a parting gift Professor Marius leaves K-9 in the care of the Doctor.

Regular cast

Leela: Louise Jameson; Voice of K-9: John Leeson;

Guest cast

Supervisor Lowe: Michael Sheard; Captain Safran: Brian Grellis; Meeker: Edmund Pegge (1); Silvey: Jay Neill (1); Crewman: Anthony Rowlands (1); Professor Marius: Frederick Jaeger (2-4); Opthalmologist: Jim McManus (2-4); Doctor Parsons: Roy Herrick (2-4); Marius's Nurse: Elizabeth Norman (2-3); Doctor Cruickshank: Roderick Smith (2-3); Doctor Hedges: Kenneth Waller (2); Reception Nurse: Nell Curran (2); Nucleus: John Scott Martin (3-4); Nucleus Voice: John Leeson (3-4); Medic: Pat Gorman (3-4);
Uncredited cast: Crewmen: Harry Fielder (1), Stuart Myers (1); Computer Voice: Anthony Rowlands (1); Bi-Al Members: Leslie Bates, Alan Clements, Margot Gordon, Derek Hunt, Kenneth Sedd, Cy Town;

First showing

Channel Episode Title Date Viewers Position
BBC 1458Part OneSat 1 October 19776:20 pm - 6:45 pm8.6M40th
BBC 1459Part TwoSat 8 October 19776:05 pm - 6:30 pm7.3M55th
BBC 1460Part ThreSat 15 October 19776:10 pm - 6:35 pm7.5M50th
BBC 1461Part FourSat 22 October 19776:10 pm - 6:35 pm8.3M50th

Repeats (on the BBC)

Outside filming

This programme does not have any outside filming

Studio filming

Television Centre Studio 6;

Bloopers and mistakes

This programme has no bloopers or mistakes. It's probably not perfect, just that they haven't been found or pointed out yet.

Notes and trivia

K-9 does not appear in part one.

Working titles

The Enemy Within; The Invisible Invader;