- Author Phobia: Robert Holmes hated filing his taxes as his role on Doctor Who combined writer (as a freelancer) and script editor (as a staffer), he was stuck in a complicated and Kafkaesque financial situation where he had to pay tax on his earnings twice. This annoyed him so much that he wrote a story about an Obstructive Bureaucrat civilization that taxes people to suicide before the Doctor inspires a populist revolt to murder them all and cheer about it.
- Creator's Favourite Episode: Louise Jameson named this as her favourite serial.
- Development Gag: Leela and the Doctor are identified as "terrorists." In real life, Leela's character was partially based on Palestinian revolutionary Leila Khaled.
- Edited for Syndication: When the story was first screened by The ABC in Australia in 1979, a small edit was made to part one by the Australian Film Censorship Board (now the Australian Classification Board) to remove the "Stuff the Company!" insult delivered by Mandrel in response to Cordo's rather nervous "Praise the Company!" Strangely, a repeat transmission of the story in 1979 was in uncut form i.e. with Mandrel's line intact as well as subsequent screenings in 1982 and the late 1980s.
- Inspiration for the Work: In addition to his gripe about his tax bill, Robert Holmes was inspired by a non-fiction book called The Iron Sun: Crossing The Universe Through Black Holes by Adrian Berry, which postulated the idea of man-made suns
- Throw It In!: The joke involving the Doctor accidentally hypnotising Leela was devised on the set by Tom Baker and Louise Jameson.
- What Could Have Been:
- At one point in scripting, the scene in which Leela is stunned when entering the large safe was to have been her death scene. However, the production team decided against killing Leela, in part because to have Tom Baker's Doctor shown grieving midway through a story would have been inappropriate both for the story and Baker's version of the character.
- The Collector was originally conceived as a large, corpulent figure, which is why Hade calls him things like "Your Immensity".
- Director Pennant Roberts had originally intended that the giant credit cards featured in the story should resemble Barclaycards. This was vetoed by producer Graham Williams who said that it would be free publicity for the bank.
- Veet's lines originally went to a character named Rashif, who was dropped from the script.
- Marn was originally a man, but was changed to avert The Smurfette Principle that Doctor Who had often been accused of.
Trivia / Doctor Who S15 E4 "The Sun Makers"