MI5 officer John Preston breaks into the residence of British government official George Berenson on New Year's Eve and finds a number of top secret NATO files that should not have been there.

Govorshin's subordinate, Pavel Borisov, complains to his old friend General Yevgeny Karpov, about his department being stripped of resources and personnel, particularly his star officer Petrofsky.

A surprised Karpov quietly investigates and learns about Petrofsky's unsanctioned mission – to violate the Fourth Protocol by assembling and detonating an atomic device as a false flag, to appear to be an American nuclear accident at a nearby military base, intended to strain British-US relations and strengthen the anti-nuclear movement in advance of an election in favour of the Soviet Union.

Preston, however has the confidence of Sir Bernard Hemmings, the gravely-ill Director of MI5, as well as Irvine, who is happy to sidestep Harcourt-Smith's directives.

Preston had become suspicious when known KGB agent Winkler was used as a courier, making it easy to follow him, and also when Petrofsky was killed instead of being captured for questioning.

Towards the end of the film, the car chase in Ipswich is actually shot in Chelmsford on the A1016 Chelmer Valley bypass which at the time was newly built.

On the rare occasions when it does rise above the material, it's because Pierce Brosnan is chillingly effective as an assassin with the body temperature of a snake.

Scott praised Michael Caine's excellent performance, but complained that the "role permits him to display only one of the three dimensions he was able to provide in his portrayal of the father in The Whistle Blower (1986).

[7] Quoted in Halliwell's guide, Daily Variety stated that "there is an uneasy feeling that the whole affair could have been better made into an excellent miniseries".

[7] John Ferguson awarded it two stars out of five for Radio Times, stating "what once made for diverting summer reading now appears tired and not particularly relevant".