ट्रिविया

John le Carré was so impressed by Alec Guinness's performance as George Smiley that, in later novels, he wrote Smiley's characterization to be in keeping with Guinness' performance.

Alec Guinness was very concerned that he wasn't the right type to portray the "frog-like" George Smiley. Three weeks into filming, he panicked and asked to be replaced, and recommended Arthur Lowe for the role of Smiley. However, he eventually overcame his doubts and went on to receive critical acclaim for his portrayal.

John le Carré has admitted that the vocabulary used in the novels/series (babysitters, lamplighters, the Circus, the nursery, moles, scalp hunters) was made up. He was later amused to discover that real agents had begun to appropriate some of his vocabulary once his espionage stories were published.

The Czechoslovakia scenes were filmed in and around Glasgow, Scotland, which producer Jonathan Powell says "was a very rough, poverty-stricken place" in 1979.

John le Carré once paid an unexpected visit to the set during filming. Alec Guinness stopped acting immediately and asked that le Carré leave so he could continue. Guinness later maintained that it was disconcerting performing with le Carré watching, as he had based a lot of Smiley's performance on the writer.