The character of George Smiley, John le Carré's hero, was renamed Charles Dobbs for this movie. This was because the Paramount Studio had bought the rights to the Smiley name when they produced The Spy Who Came in from the Cold (1965).

Cinematographer Freddie Young invented a process of pre-exposing color film negative to a controlled small level of light so as to mute the color. This process was called pre-fogging or flashing and this was the first ever film to use this. This movie's director Sidney Lumet labelled the process "colorless color".

In this film, James Mason was the second actor to play John le Carré's famous George Smiley character on screen and TV though the character was renamed Charles Dobbs for this movie. Rupert Davies was the first actor to play him in The Spy Who Came in from the Cold (1965); Sir Alec Guinness was the third, he played him twice, in Tinker Tailor Soldier Spy (1979) and Smiley's People (1982). Denholm Elliott was the fourth actor to play Smiley in A Murder of Quality (1991) whilst Gary Oldman is the fifth actor to play him, in Tinker Tailor Soldier Spy (2011).

Second and final screen adaptation of a John le Carré story scripted by Paul Dehn. The first had been The Spy Who Came in from the Cold (1965) released a year earlier. Just before that, Dehn also co-wrote the script for the James Bond movie Goldfinger (1964).

John le Carré was not wildly impressed by this screen adaptation of his novel: 'It had a cast to dream of: Mason, Maximilian Schell, Simone Signoret, Harry Andrews, Roy Kinnear - not to mention a beautiful young female Scandinavian actor who to my astonishment stripped naked, which in the Swinging Sixties was a kind of necessary dare [i.e. Harriet Andersson]. The sight of her so impressed me that I left the cinema thinking of little else. When I came to my senses, I had an impression of an assembly of nicely shot cameos that didn't quite add up.'

The film's source novel title 'Call for the Dead' was changed to 'The Deadly Affair (1967)' for this movie as this was a more commercial title.

The character of Hans-Dieter Mundt (played by Peter van Eyck in The Spy Who Came in from the Cold (1965)) was changed to Dieter Frey for this movie because the Paramount Studio held the rights to that character's name from that movie.

This is the only film in which siblings Corin Redgrave and Lynn Redgrave both appear.

Actress Candice Bergen was the first choice to play Charles Dobbs' (James Mason's) unfaithful wife Ann Dobbs. The part went to Harriet Andersson.

Excerpts of plays seen in this film include scenes from William Shakespeare's 'Macbeth' during rehearsal and 'Christopher Marlowe''s 'Edward II' performed by the Royal Shakespeare Company and directed by Peter Hall.

One of three filmed cinema movie adaptations of John le Carré spy and espionage novels that were made and released during The Golden Age of Spy Movies during the 1960s. The three theatrical feature films are The Spy Who Came in from the Cold (1965), The Deadly Affair (1967) (based on le Carré's novel "Call for the Dead"), and The Looking Glass War (1970).

Writer John le Carré partially based his famous George Smiley character (in this film renamed as Charles Dobbs) on a friend, the Lincoln College tutor and Oxford University don, the Reverend Vivian Green. Smiley was also based on le Carré's boss at Mi5, Lord Clanmorris, who wrote crime novels under the pseudonym of John Bingham.

First theatrical color movie of a John le Carré story. The Spy Who Came in from the Cold (1965) was in black-and-white.

Nineteen years after the film was released, Corin Redgrave (David) became the brother-in-law of Petra Markham (Daughter at theatre) when he married her elder sister Kika Markham in 1985. The film's cast also includes his younger sister Lynn Redgrave.

Screenwriter Paul Dehn actually worked as an operative during WWII, and was involved in the death of several enemies.

The first film of Timothy West.

This movie was made and released about five years after its source novel ('Call for the Dead') by John le Carré was first published in 1961.

This film is based on John le Carré's first novel.

The film's source novel 'Call for the Dead' was first adapted for radio as a BBC Radio 4 drama in 1978.

Opening credits: All characters and events in this film are fictitious. Any similarity to actual events, or persons living or dead is purely coincidental.

The ending of this film is somewhat different from that of John le Carré's original novel. The end has Charles Dobbs discovering that his close friend has been having an affair with his wife and that he is in fact an enemy agent who has cynically initiated the affair as a way of keeping a surreptitious watch on Dobbs's activities. This is very similar to the ending of le Carré's later and more famous novel, 'Tinker, Tailor, Soldier, Spy', which was not published until six years after the appearance of this film.

Body count 6.