Fred Freiberger's hiring of writer Terrance Dicks (a frequent script editor for Doctor Who (1963)) was a complete accident, Freiberger mistaking him for another writer. Although "The Lambda Factor" was considered a decent episode, Freiberger failed to use him further, and didn't even invite him for the screening of this episode upon completion. According to Dicks, he wasn't even aware that his script had been filmed until years later, and when he finally saw it on TV, he was amazed that the finished episode was virtually identical to his submitted script - very rare with Freiberger in control.
Unlike Alpha waves and Beta waves, which are actual brainwaves mentioned by Helena, Lambda waves and the Lambda Variant are fictitious, concocted by writer Terrance Dicks for the episode.
The chimpanzee brought onto the set ended up urinating on the Command Center consoles, forcing the cast and crew to endure the odor for weeks to come.
Filmed September 29th through October 15th 1976.
The booth used to block the Lambda Variant was also seen on Death's Other Dominion (1975), Mission of the Darians (1975), Journey to Where (1976), and Devil's Planet (1977).