- Big-Lipped Alligator Moment: Prideaux snapping a bird's neck after it flies through his classroom window and frightens his students. Justified in the original novel, as it foreshadows how Prideaux would kill Haydon, but it ends up being rather baffling in the movie, where Prideaux nails Haydon with a rifle instead.
- It also demonstrates how on edge Prideaux could be, how brutally violent he could be, and how unhinged he was that he didn't give a thought to how it would impact the schoolboys.
- Also, Lacon buttering a toast really, really loudly during his meeting with Bland and Alleline.
- Narrowed It Down to the Guy I Recognize: A lot of viewers guessed that the traitor is Colin Firth's character purely on the strength of him being Colin Firth.
- The fact that the actor received second billing on the movie poster may have also been something of a giveaway.
- Nightmare Fuel:
- A quick shot of Irina's husband sitting in a bath full of blood with his guts ripped out.
- The Cold-Blooded Torture that Prideaux is put through is pretty brutal, including being forced to listen to a tape that is nothing but intermittent white noise and screaming. Even worse is the fact that his torturers seem utterly bored by the whole thing, like they just want to get it over with. Of course there's also the fact that Prideaux is Forced to Watch as Irina is shot in the head in front of him, and Pretty Little Headshots does NOT apply here. No wonder he was so fucked up by the experience.
- One-Scene Wonder: Patrick Stewart as Karla in this miniseries and later in Smiley's People. He doesn't even speak a single word during his one scene in each series, but is still captivating. It doesn't hurt that for Sci-Fi fans, the scene is basically Obi-Wan Kenobi and Captain Picard sharing the screen.
- Squick: In the film adaptation.
- The baby continuing to suckle on the woman's breast after she's been shot dead.
- After Irina is shot in the head, there's a lingering shot of Prideaux doing a Thousand-Yard Stare at the wall, which is covered in Irina's brain matter and blood. The shot ends with a piece of her brain peeling off the wall with a squishy plop sound.
- They Changed It, Now It Sucks!: Peter Hitchens' review of the film was essentially a point-by-point list of every alteration from the novel, and why each was a change for the worse.
YMMV / Tinker, Tailor, Soldier, Spy