Storyboard - The Traitor (1983)

Secret Service agent Michael Fawkes has been given the job of tailing a man called Slade, a scientist who has recently defected from Russia who is suspected of being a Russian spy. But when Fawkes reports back to his boss, Palfrey, he informs him that nothing happened. Has the suspect been warned? British Intelligence thinks so and suspect a spy in their ranks. Quite who it is could be closer than they think, with each man suspecting the other...

Starring Alec Cowan, Tim Piggott-Smith, Antony Brown, Gary Watson, Keith Edwards, Georgine Anderson, Ian Barrett, John Quarmby, Michael Sheard, David Gillies, Simon Watkins, Philip Ettington and Walter Henry. This comes from the anthology series Storyboard and was originally broadcast on August 23rd 1983.