A Dandy in Aspic

A Dandy in Aspic (1968)

Directed by Anthony Mann ((Laurence Harvey (finished film after Mann died) (uncredited))
Laurence Harvey
Tom Courtenay
Mia Farrow
Lionel Stander
Per Oscarsson

Wikipedia: "Essentially a Cold War thriller, it is the story of a Russian counter-espionage agent, known as Eberlin (Laurence Harvey) to his employers in British Intelligence, where he is working undercover for Moscow as a double agent."