Michael Caine portrays "Harry Palmer," who is known to his superior, “Ross” (Guy Doleman), as something of an annoyance. It’s therefore enjoyable when he's reassigned to the department led by "Dalby" (Nigel Green). His assignment involves a complex scheme to abduct and brainwash prominent scientists. “Palmer” has reservations about the mission, suspecting that he may have been selected with the expectation that he won't survive. As he investigates, he begins to suspect something is amiss within his organization and understands that neither of his bosses fully trust each other. Will he manage to live long enough to unravel the mystery? This is a captivating version of Len Deighton’s novel, featuring Caine in excellent form as the somewhat reluctant man trying to figure out who's manipulating whom. Nigel Green also performs admirably; after establishing its rhythm, the film becomes an absorbing political thriller that provides a glimpse into how psychological manipulation can function – both directly and subtly. The beginning might feel slightly protracted, but once it gains momentum, it’s enjoyable, and despite repeated viewings, I still struggle to recall the ending.

Source on TMDB