That endless corridor that the team were always dashing around the ship in was only about 20 feet long with a short tee on one end.
Gareth Thomas and Tom Baker always wanted to do a cross-over between "Doctor Who" (1963) and Blake's 7 (with the two heroes passing each other in a corridor, exchanging greetings) but this was vetoed by producers of both series. Indeed the invasion from Andromeda at the end of the second season was originally going to be invasion by Doctor Who's Daleks, also created by Terry Nation.
The series was originally to have ended with the climax to the third season. However, the BBC One Controller of that time, Bill Cotton, was so impressed by the quality of the series that he had the continuity announcer declare that Blake's 7 would return for a new series the following year, which caused some surprise amongst the cast and crew. Chief of the problems this caused was that producer David Maloney had become producer on "The Day of the Triffids" (1981), meaning that a new producer was needed for the show. After Terence Dudley turned the job down due to his intending to retire, Vere Lorrimer was made producer.
Paul Darrow (Kerr Avon), Michael Keating (Vila Restal) and Jacqueline Pearce (Supreme Commander Servalan) are the only cast members to have stayed with the series throughout its entire run.
Michael Keating (Vila Restal) is the only actor to appear in all 52 episodes of the series.
Gareth Thomas (Roj Blake), Michael Keating (Vila Restal) and Mike Mungarvan (Prisoner/Duty officer) are the only actors to appear in both the first and last episodes of the series.
Scaramanga's huge laser gun from the James Bond film The Man with the Golden Gun (1974) was one of many props bought from Pinewood Studios by the BBC, and appears here in the early episodes of Blake's 7 as the main console of the prison ship London.
Creator Terry Nation pitched the show to BBC executives off the cuff, having made no notes or outlines. He started talking about The Dirty Dozen (1967) in space, and made up the rest as he went along.
Gareth Thomas revealed in "The Cult of...: Blake's 7 (#1.5)" (2006) that he became disillusioned with some aspects of the series, in particular what he regarded as its move away from science fiction and into science fantasy. When he asked if he could direct a couple of episodes and this was refused by the BBC, he decided to leave.
Producer David Maloney's first choice for script editor was Robert Holmes. Holmes declined the offer but recommended Chris Boucher, who got the job instead.
Sally Knyvette (who played Jenna during the first two seasons) is the only cast member not to have an on-screen kiss during her tenure on the series.
Nick Tate, Duncan Preston, Paul Seed and Andrew Ray were amongst those looked at to play Tarrant, as the character was originally conceived as an older captain figure than was eventually used.