- Accidentally-Correct Writing: Some situations were conceived as fiction, but were later revealed to have real-life counterparts. For example, "The Compassionate Society" depicts a hospital with five hundred administrative staff but no doctors, nurses or patients. Jonathan Lynn recalls that "after inventing this absurdity, we discovered there were six such hospitals (or very large empty wings of hospitals) exactly as we had described them in our episode."
- Later documentaries have revealed that Jay and Lynn had sources in Whitehall that helped them with ideas for stories and scripts, including high-ranking officials like Marcia Falkender and Bernard Donoughue, the latter of whom provided the original story that inspired the first half of "The Moral Dimension", where Hacker and staff conspire to smuggle alcohol into a reception in a Muslim country.
- Actor-Shared Background: Hacker, Sir Humphrey, and Bernard share birth dates (and dates of death where applicable) with the actors who portrayed them.
- …But I Play One on TV: When Paul Eddington visited Australia during the 1980s, he was treated as a visiting British PM by the then Australian leader, Bob Hawke, who was a fan of the show. At a rally, Hawke said "You don't want to be listening to me; you want to be listening to the real Prime Minister", forcing Eddington to improvise.
- Creator's Pest: The writers realised that Frank Weisel didn't work as a character, so they dropped him after the first season.
- Dawson Casting: Bernard's age is never stated on screen, but various hints suggest he's supposed to be a fairly young rookie civil servant, probably in his late twenties, much younger than Derek Fowlds at the time.
- Harpo Does Something Funny: Or in this case, as writer Jonathan Lynn reports putting in the margins of scripts, "Paul doesn't have to say this line if he doesn't want to". Paul Eddington, who played Hacker, had an amazing ability to convey the same sense a line was intended to give with an expression. One particularly good example is 1:10 to 1:30 or so in this clip. In ten seconds, Hacker's expression goes from joyful surprise, to horror that he's let himself look so pleased, then regret, then forced sadness (frowning hard so as not to betray his delight), then a sort of statesmanlike concern, then he shakes his head gravely and says "Tragic."
- The Shelf of Movie Languishment: The Pilot, "Open Government", was produced in 1979 but not transmitted until 1980 in fear that it could influence the results of the 1979 UK General Election.
- Throw It In: The moment in "The Official Visit" where Bernard's briefcase falls open and lets his files spill out on the station platform was unscripted — in fact, Derek Fowlds actually said "oh, shit!" when it happened, which somehow made it into the finished episode (probably because it was only just audible over the noise of the trains).
- Not surprising; Derek always said "shit" every time he goofed.
- Uncredited Role: Pauline Quirke as Nelly in "The Economy Drive".
- Wag the Director: Paul Eddington, a firm believer in nuclear disarmament, once convinced the writers to rework the script of a Yes, Prime Minister episode that he believed was rather too flippant about nuclear war.
- What Could Have Been: The 2013 series started development at The BBC, where the original series had aired, but negotiations broke down when the BBC only wanted to commission a pilot episode and then decide based on that whether to order a full series. The creators told them that they would only accept a commission for a full series, and that the BBC could take it or leave it — they opted to leave it, with the series eventually being produced by UKTV Gold.
- Written-In Infirmity: In Yes, Prime Minister you might notice that in the later episodes especially, Jim Hacker spends much of the show sitting still behind his desk or in his armchair at home. This is because at the time of filming, Paul Eddington was suffering from T-cell lymphomanote and the episodes were written to be as comfortable for him to perform as possible.
Trivia / Yes, Minister