Based on the same real life events as Another Country (1984), Cambridge Spies (2003), History in Faces: Cambridge Five (2011), Philby, Burgess and Maclean (1977), A Question of Attribution (1991), An Englishman Abroad (1983), Tinker Tailor Soldier Spy (2011), Tinker Tailor Soldier Spy (1979), Traitor (1971), Blade on the Feather (1980), The Jigsaw Man (1983) and influenced the source novels of The Fourth Protocol (1987), The Innocent (1993) and others works such as A Different Loyalty (2004) and Olding (2019), even in minor form like in The Imitation Game (2014).
To date, all the DVD releases of this film prominently feature photographs of actor Anthony Hopkins. However, it is in fact the less "bankable" actor Ian Richardson who plays the leading role, and title character, of Anthony Blunt.