Sorry, looks like MTV-ready crap, sex scene and all.
TTSS happens to be one of my all-time favorite movies and LeCarre my favorite author after Shakespeare. Back when, I had the whole series taped from PBS, AND I bought a PAL-format VHS set from England and had it dubbed into NTSC by some Pakis down on Devon in Chicago, just so I could OWN a copy.
The original BBC series followed the book chapter by chapter, scene by scene. Alec Guinness, Ian Holm, Ian Bannen, even Jean Luc Picard Patrick Stewart, a whole list of top-notch English actors who disappeared in their roles.
Sad thing is, I will probably go see it just because I so love this book.
Smiley's People is the follow-on story, and there is a DVD of that as well. Good thing they never made Honourable Schoolboy into a movie - that book put me into a seriously nasty depressed, nasty FOUL nasty mood for 3 weeks.
Spy/Cold starred the inimitable Richard Burton, and they also made Tailor of Panama into a movie (feh! ptooey) with Pierce Brosnan and Jamie Lee Curtis (who once again stripped naked to show off her rack), as well as Russia House (meh) with Sean Connery and Michelle Pfeiffer who IIRC did not strip naked.