Ability over Appearance: Tarrant was originally written as a man of 35-55. When 24-year-old Stephen Pacey was cast, the character was changed from seasoned veteran to cocky young upstart.
Acting for Two: In "Children of Auron", Jan Chappell plays both Cally and her twin sister Zelda, which makes sense because they're both clones of a single, unnamed parent. She also plays an alien being that bases her appearance on Cally's in "Sarcophagus". Tarrant also had a lookalike brother (with a bouffant wig) in "Death-Watch".
Bad Export for You: It's currently not available on DVD in the US, though you might be able to scrounge up some VHS tapes.
Cast the Runner-Up: Paul Darrow and Brian Croucher were both considered for Blake before being cast as Avon and Travis Mark II.
Josette Simon did not look back on the show with fondness, believing that the showrunners took advantage of her naivety and lack of confidence to get her to play a "hot exotic warrior woman" part that she saw retrospectively as both sexually and racially demeaning.
Jacqueline Pearce was unhappy with the final season, claiming that it ran out of steam and ideas. That said, she named "Sand" from that season as her favourite episode.
When it comes to individual episodes, Michael Keating's least favourite was "Ultraworld" and Stephen Pacey allegedly disliked "Assassin" because it made Tarrant look like a gullible idiot.
Dawson Casting: Possibly the case with Dayna: though Josette Simon is actually quite a lot younger than other members of the principal cast, she was still in her early twenties when the show was made, but at several points it seems like the character was meant to be in her mid-teens (such as when she refers to herself as a "girl" at one point, explicitly contrasting this with Cally's allusion to herself as a woman moments before). A lot of her other traits (her obvious sexual curiosity around Avon and Tarrant, her quite childlike desire to be comforted when frightened despite her usual badass demeanor) could be meant to indicate that the character was intended to be younger than she looked, but might just as easily be put down to her isolated upbringing alone with her father and foster-sister.
The series is full of unexpected explosions: the reactions (shrieking and/or being thrown through the air) were often genuine, because the directors neglected to warn the actors about just what was going to go off and where.
The ending is a crossover of this and Wag the Director: Gareth Thomas was fed up with the show and really determined that Blake would be so unambiguously dead that there would be no way to bring him back if the show got renewed again. Therefore at every opportunity he went back to the special effects crew to ask them to put another Squib and bloodbag under his costume. As a result, when the shooting scene finally happened the blow to his chest was hard enough to really wind him and leave him cut and bruised.
Executive Meddling: The series had wound down after Series 3, with a solid ending that satisfied most everyone involved. That was, until the cast and crew were watching the programme during a party, only to hear the announcer mention that Series 4 would air later that year. It was the first anyone — supposedly including the writers themselves! — had heard about a fourth series,note Allegedly the Head of BBC Television was watching the episode at his home, and was so impressed he rang the presentation department and requested the show's return to be announced at the end of the episode and some were contractually obligated to other things. The slap-dash nature of things required killing one cast member and finding a replacement quickly, as well as designing and building a new ship for the crew to fly, as The Liberator was destroyed at the end of Series 3.
Killed by Request: One of the most famous examples in British TV is Gareth Thomas, who played Roj Blake. He left at the end of the second season, when the character was Put on a Bus, but got fed up when he was called back for a second return appearance in the final episode of the fourth season. Unaware that it would turn out to be the last episode of the show anyway, he refused to do it unless he was absolutely and unambiguously Deader Than Dead at the end, and actually conspired with the effects team to make it one of the bloodiest TV shootings of the era, with so many Squibs being loaded onto his chest and stomach that it narrowly avoided breaching contemporary taste and decency standards and left him with slight physical injuries when they all went off.
No Budget: The series was allocated the same budget by the BBC as Softly Softly Taskforce, a low-key contemporary police procedural which it was replacing. The per-episode effects budget, for example, was £50. Expect to see plenty of sets, costumes, and props nicked from Doctor Who, or perhaps some baking tins stuck on the walls. The special effects designer spent his budget for the entire series on the first episode to be filmed, "Space Fall", because A New Hope was debuting at around the same time. The actual first episode, "The Way Back", went so far over budget it affected the rest of the season and became one of the best stories in the series.
No Stunt Double: Paul Darrow performed most of his own stunts. In retrospect, he thought he must have been mad, as some of them were quite dangerous.
Post-Script Season: The show ended its third season with the destruction of the Liberator and the (apparent) death of Servalan. When the fourth season opened, they had to take the show in a radically different direction to compensate for the changes.
Rule 34 Creator Reactions: Paul Darrow (who played the show's initial Lancer and later protagonist Avon) was 'very very seriously unhappy about fics depicting his character engaging in m/m sexual activity (a particular problem as Avon was the show's Launcher of a Thousand Ships, most of which were slash). This interacted with other fandom conflicts to create a humungous fandom civil war.
Science Marches On: According to Chris Boucher, the writers talked over the series with Doctor Christopher Evans at the National Physical Laboratory, who liked all the concepts (except telepathy), even the teleport which he considered would happen sometime, "and it was in ''Star Trek so what the hell." With the audio series, the teleport is dropped for being unrealistic (but ironically they keep Cally's telepathy).
Talking to Himself: Peter Tuddenham, in scenes where Orac was talking with Zen or Slave. Tuddenham could reportedly do this with no need for ADR, he simply used two different microphones, one for Orac and one for Zen/Slave. That said, there are only a *very* small number of scenes in which the computers talk to each other.
Technology Marches On: Most obviously in the solid-state computers that Avon reprograms by rewiring their circuits.
Torch the Franchise and Run: Terry Nationtried this with the end of Season 3. He torched the Liberator, revealed the "Blake" they found to be a hallucination, stranded the crew on the rear end of the galaxy, etc. That didn't work. Undeterred, Chris Boucher made damn sure to try harder torching the replacement ship, and all the cast at the end of the following season. This time, it worked.
UnCancelled: Apparently the first anyone knew of the fourth series was when it was announced at the end of the last episode of the third. The BBC's Director of Television, Bill Cotton, was enjoying the episode so much he phoned the transmission staff mid-episode and told them to announce that the show was returning.
Pip and Jane Baker submitted an unused episode called "Death Squad", in which Blake, Gan and Jenna would infiltrate a Federation facility attempting to create 'super-soldiers' by administering drugs to humans, leading to Blake and Gan becoming exposed to the drugs and Jenna being held by Servalan as an inducement for the scientist behind the plan was abandoned. This was ostensibly on cost grounds, although Boucher had concerns about the quality of the script.
An unused episode from Series C would have seen the crew searching for Blake and finding his grave.
During a writer's strike Paul Darrow wrote an episode script for Series D in which the crew desert Avon, marooning him, concentrated on Vila being more heroic than he had been for that series and also being the one who saves Avon by convincing the others to go back for him. Chris Boucher said no. Another rejected Darrow script, "Man of Iron" (involving an android called Gabor), is available to buy from the official Blake's 7 fan club. It's reputedly terrible.
Terry Nation wanted the invading aliens in the series 2 finale to be the Daleks, and both Gareth Thomas and Tom Baker pushed for a 'Blake's 7/Doctor Who'' crossover where the Doctor and the crew meet up, but the BBC vetoed both ideas.
The first proposal for the series' conclusion, titled "Attack", involved Blake returning to lead an assault on the Federation on Earth, finally defeating them. This idea was rejected by producer Vere Lorrimer, who thought it "...would be like five men trying to defeat the German army".
Travis was originally going to be the Big Bad of the series, with Servalan just the commanding officer who he reported to in his first appearance. Instead, Servalan herself became the show's main villain, with Travis acting as The Dragon for her for the first season-and-a-half, before going rogue in the second season.
Servalan almost didn't appear in the final season, as she was seen to be killed off in the third season finale. Furthermore, Jacqueline Pearce was hospitalised with an illness. The creators devised a new villain, Commissioner Sleer, as the new Big Bad. Pearce recovered and returned to the series and Sleer became an alias of Servalan.
Cally was originally going to have red skin and hair and her eyes would turn black when she entered an alien trance (Jan Chappell would wear contact lenses to create the effect). These ideas were abandoned for being too costly.
Robert Holmes was asked to be the script-editor for the series. He declined, having just left the script-editor's post on Doctor Who, though he did recommend Chris Boucher for the job. Holmes also wrote four episodes of the series.
When Gareth Thomas left the series, there were talks of recasting Blake.
On that note, Thomas left the series when the BBC wouldn't let him direct any episodes. One could only imagine what he would have done.
And one can only wonder what the fifth season would have been... though it's highly likely that, at the very minimum, Dayna would have been killed off due to Josette Simon having already started to become disillusioned with the series even during the fourth season. Also, Glynis Barber revealed in a 2006 interview that she wouldn't have returned, so that would make Soolin dead as well.
Written by Cast Member: Paul Darrow wrote an official spin-off novel, Avon: A Terrible Aspect, which as the title suggests concentrated on his character, and explains Avon's early life and the events that led to him being imprisoned for internet fraud. He also wrote the "Lucifer" trilogy, featuring an older Avon after the Kill 'Em All finale. During production he wrote a script called "Man of Iron", but it was rejected.
The Other Darrin: The voice of Zen and Orac in the Big Finish audios is Alistair Lock, replacing Peter Tuddenham who passed away in 2007. Yasmin Bannerman also came on to take the role of Dayna, as Josette Simon declined to return.
Role Reprisal: In A Rebellion Reborn, Michael Keating as Vila and Jan Chappell as Cally or at least a Cally.