Factual error: George Smiley stays in a hotel near Liverpool St Station, London to investigate the spy at the heart of the circus. There is one scene where we see, from above, a train leaving the station. Liverpool St station is electrified using overhead wires - the train is leaving a station using a different electrification system called 3rd rail which has never existed at Liverpool St.
Factual error: Control seems to have left behind some turntable package material for a deck called Dual CS 505-1. This model, however, only went to production in 1981.
Plot hole: Smiley is at a hotel asking Sam what happened when he was duty officer on the night Jim Prideaux was shot. What Sam recalls (among other things) is he and Bill Haydon going through Jim's things. Haydon finds a photo of himself and Prideaux and sneaks it away in his pocket unseen by Sam. How could Sam explain that to Smiley when he did not see Haydon's move?
Continuity mistake: Bill Haydon is on a call with the Hungarian embassy. He's holding his phone in his right hand talking on it, but then slams it down with his left hand.
Suggested correction: Watch the scene, he lowers the receiver to speak to Jerry and his hands come together on the receiver, the camera cuts to Jerry, then back to Haydon hanging up the phone with the left hand, closest to the cradle. Watch it again, seems to match correctly.
Visible crew/equipment: In the scene on the runway a sound man with a boom mike is reflected in Smiley's glasses.
