Tim McInnerny's character was originally named Captain Cartwright. Stephen Fry had the idea to change it to Darling (named after a boy at his school) and created a running gag which is frequently used throughout the series.
Tim McInnerny affected a nervous tick in his eye for the character of Captain Darling, but after the six-week rehearsal and shooting schedule was over, the tick had become second nature and it took him a further two months to get rid of it.
During rehearsals, the script was exhaustively discussed and redrafted by the cast, with Richard Curtis having the final say on the content. Stephen Fry, Hugh Laurie and Rowan Atkinson were comic writers/actors themselves, and having worked together on previous Blackadder series were not afraid to question the script and make suggestions. However, this caused tensions to arise between the writers and the cast; in interviews Ben Elton felt that they had allowed the cast to question every aspect of the script, while Tony Robinson claims "the writers felt we were unilaterally altering the script for the worse; by the end, they felt we had run away with it." The ill-feeling between the writers and actors, coupled with the draining scripting and rehearsals led to everyone deciding not to make more Blackadder shows.
Writers Ben Elton and Richard Curtis wrote the episode scripts separately using word processors, and then swapped floppy disks containing their scripts with each other to edit jokes/dialogue. Curtis says that they always wrote separately, because if they were in the same room they would discuss anything BUT Blackadder. He also recalls that they stuck to a policy whereby if one removed a line for not being funny, then it was never put back.
The writers researched World War I and thought it made a very apt fitting for a comedy: "All the buildup to the First World War was very funny, all the people coming from communities where they'd never bumped into posh people, and all being so gung-ho and optimistic... the first hundred pages of any book about the World War are hilarious, then of course everybody dies." Rowan Atkinson further explained that the trenches of WWI were perfect: "We wanted a place and time that could reproduce to an extent the claustrophobia and sordidness of medieval England, the best way to do that was to set it in the middle of a war."
Tim McInnerny had declined to continue his role as Lord Percy or take the part of the foolish Prince George in Black Adder the Third (1987), for fear of being typecast as an idiot; as a consequence, his part in the fourth season is much more shrewd and wicked than any of his earlier characters.
The "Blackadder" theme and the series music were performed by the band of the Third Batallion, the Royal Anglian Regiment. At the time they were a full time infantry battalion but now are a part time volunteer T.A. battalion.
The decision to set Blackadder in the trenches of World War One did not come from Ben Elton, Richard Curtis or any of the cast or producers. The BBC received an unsolicited script for a new Blackadder series set in a France during WWI, from a young first-time writer. Elton and Curtis felt that the script itself was not good enough, but liked the WWI setting, and subsequently wrote Blackadder Goes Forth using this idea.
According to John Lloyd, the popularity of the series within the armed forces meant that one point, half of all regimental goats had the name 'Baldrick'. Further evidence of the show's popularity can be seen from records of the first Gulf War, during which the British lines in Iraq were named after characters from the series.
General Melchett's mannerisms include a laugh or exclamation that sounds like a bleating sheep. This is an inside reference for the fans of Black-Adder II (1986), in which Lord Melchett was revealed to have an unnatural attraction to farm animals.
The trivia items below may give away important plot points.
According to Rowan Atkinson, he'd started to experience his character's apprehension in the interim to the final episode Blackadder Goes Forth: Goodbyeee (1989): "in the weeks leading up to the recording of that final episode when we went over the top, for the first time in my acting career...knowing that even though the rest of the episode was its usual standard funny sitcom self, there was this deep twist in my stomach throughout that week thinking along with your character that you were doomed. It was most peculiar."
Rowan Atkinson was personally not fond of filming the final shot in the finale Blackadder Goes Forth: Goodbyeee (1989), stating that running towards the camera and falling to the ground with the rest of the actors felt unconvincing. This led to the slow motion shot and fade to the poppy fields during editing.
The show has come under criticism by historians for presenting an oversimplified view of the war and enforcing the popular notion of WWI being "lions led by donkeys" (brave men led by buffoons to their death). One critic asked, "Is the series justified in using tragic situations as a springboard for comedy merely for entertainment value?" However some critics say the characterization and sense of danger prevented the sitcom from trivializing its subject matter: "The prospect of its characters suddenly dying a violent death provided a constant source of tension and gags, though when they really were killed off at the end of the final episode Blackadder Goes Forth: Goodbyeee (1989)...the result was so unexpectedly moving that the programme was later repeated as part of an otherwise wholly serious BBC2 Armistice Day programme without anyone batting an eyelid."
Ben Elton's uncle, historian Geoffrey Elton, had initially voiced his concern to his nephew that the show might be considered disrespectful. After the bittersweet series finale Blackadder Goes Forth: Goodbyeee (1989), Geoffrey called Ben to say that he had been wrong.
Alongside the "later incarnations" of regular characters Blackadder, Baldrick, George, and Melchett, this series is noted for presenting "descendant" versions of two fan-favorite one-off characters from Black-Adder II (1986): Bob/Kate (Gabrielle Glaister), and Flashheart (Rik Mayall). The series also includes previous regulars Tim McInnerny and Miranda Richardson in roles completely different from their prior characters.
The series was originally to end with Blackadder, Baldrick, Darling, George and all the troops being gunned down instantly by machine gunfire in the big push, when they jump out from the trench and Captain Blackadder was revealed to had feigned his death and was the only survivor.