The Whistle Blower (1988)

Robert Jones (Nigel Havers), a Russian linguist working for a British intelligence agency, is found dead, apparently having committed suicide. However, his father, Frank (Michael Caine), fails to believe Robert took his own life so decides to investigate the death himself. Jones' investigations unearth Cold War paranoia and put his own life in danger from government agents whose only agenda is to preserve Britain's foreign relations, no matter what the cost.