Revealing mistake: Just after the Trojans' conversation, there are two jolts. Lister jumps back too soon on the second jolt. (00:03:30)
Visible crew/equipment: When the crew are in their sleeping quarters, and Rimmer is talking to the others, a blue boom mic can be seen hovering over his head (you can see this if you watch the dvd on your pc, as some tv's can cut off the edge of the picture) (00:03:10)
Continuity mistake: When Lister takes the milk from his locker, keep an eye on his duvet. In the next shot when he pours the milk, it has moved and is hanging down from his bunk. The red mug on the table also moves from near the magazines to near the ashtray on the other side of the table. (00:14:35)
Deliberate mistake: In the first few series, it is suggested Lister and Kochanski barely know each other. In 'Balance of Power' Holly says that Lister has only ever spoken 173 words to her. However, by series 4 Kochanski is referred to as Lister's ex-girlfriend with whom he shared a relationship. In the series 4 documentary, Doug Naylor explains that Lister's attitude towards Kochanski was immature in the first series which is why they changed his back story from wanting to be with Kochanski to actually having been with her by series 4.
Factual error: The justice computer states that Rimmer is guilty of 1,167 counts of 2nd degree murder, each carrying a sentence of 8 years, giving a total of 9,328 years. This is equivalent to 1,166 counts. 1,167 counts would be 9,336 years. (00:14:00)
Continuity mistake: Lister screws in Kryten's replacement head (the one without the 'guilt chip') in exactly the SAME direction that he unscrewed the original head (to be exact - clockwise) (00:09:50)
Visible crew/equipment: When talkie toaster says 'light speed' a crew member can be seen in its reflection wearing a yellow t-shirt and jeans. (00:17:35)
Continuity mistake: At the start of the episode, it is clear that the capsule fully rotates and the "contents: 2" sign is not on the capsule. (00:01:05)
Other mistake: When Lister (in Rimmer's body) pleads the Cat to lend him his body, he says "how else can I pilot White Midget?" In the next scene, the Blue Midget is being piloted, and White Midget was originally abandoned for Starbug. (This mistake was admitted by the crew). (00:21:45)
Visible crew/equipment: When Rimmer and his seven kids get out of the car, three crew members and a white production truck are visible in the reflection. (00:25:15)
Continuity mistake: When the tent disappears, Lister's locks are over his right shoulder. In the next shot they are over both shoulders. (00:10:00)
Quarantine - S5-E4
Continuity mistake: When Kryten injects the luck virus into Lister's neck, the gun disappears from Kryten's hand between shots. (00:23:25)
Answer: The cello is a large four-stringed instrument, which, when it is played, stands vertically on the floor between the player's legs (assuming they are seated). If it is to grow as large as the other instuments mentioned will, it would require a rather unseemly lack of femininity to be able to encompass it with the legs.
Rooster of Doom