'The Cybernauts' by Philip Levene

Important industrial businessmen are killed in incidents involving broken necks, shattered doors, and bent shotgun barrels. Steed and Mrs. Peel investigate, initially believing the murderer to be a karate expert. They soon find that the trail instead leads to an automations expert, Doctor Armstrong, and that the killer is not flesh and blood, but a deadly robot known as a Cybernaut, built by Armstrong as part of a plan to obtain exclusive rights to a new electronic circuit, which would allow him to create machines capable of replacing humans. As Steed tries to stop Armstrong's scheme, he realises that the pen he gave Mrs. Peel is leading a deadly Cybernaut straight to her...

Patrick Macnee (John Steed), Diana Rigg (Emma Peel), Michael Gough (Doctor Clement Armstrong), Frederick Jaeger (Benson), Bernard Horsfall (Jephcott), Burt Kwouk (Tusamo), John Hollis (Sensai), Ronald Leigh-Hunt (Lambert), Gordon Whiting (Hammond)

Directed by Sidney Hayers
Produced by Julian Wintle

TX:
UK: 16th October, 1965

Notes:
*Featuring John Steed and Mrs. Emma Peel

* The tag scene: Steed is sitting in a horseless carriage doing a crossword puzzle when his pencil breaks. Mrs. Peel offers him a pen but he refuses, so she speeds off in her Lotus.