A KGB agent tricks Maxwell (John Ringham) into kidnapping the Soviet deputy foreign minister and his secretary.
Drummond (Clive Francis) asks Chapman's (Nicholas Lyndhurst) help in getting rid of a newly appointed supervisor (Dinah Stabb).
An unprepared Chapman (Nicholas Lyndhurst) is chosen to evaluate the credibility of two Russian fighter plane scientists.
Sarah's (Serena Evans) career is jeopardized by her husband's (Nicholas Lyndhurst) actions during an undercover operation.
Drummond and Maxwell vie for a role in a promotional video.
After Chapman (Nicholas Lyndhurst) is kidnapped, a Chinese Secret Service agent (Nicholas Lyndhurst) attempts to replace him at MI5.
Chapman (Nicholas Lyndhurst) has a fight with his wife (Serena Evans) after spending the night with a KGB agent.
A comedy of errors is the result when MI5 steals a Russian decoding device.
Terrorists interrupt a party at an embassy which MI5 has bugged. With Nicholas Lyndhurst and Michael Percival.
MI5's Maurice Drummond bets against MI6's leader in an interdepartmental challenge.
Drummond (Clive Francis) still suspects Maxwell (John Ringham) is a Soviet mole.
A former senior member of MI5 returns and identifies Maxwell as a KGB officer.
Chapman (Nicholas Lyndhurst) and Maxwell (John Ringham) break into a publisher's office looking for a manuscript.
Agents are told to investigate an MP who wants to unify MI5 and MI6.
A pushy CIA agent and MI5 look for a plane and its radar-defeating black box. With Nicholas Lyndhurst.
Drummond sends Chapman to bug an activist group's headquarters.
A KGB officer misidentifies who shot him; Chapman becomes a killer's target.
A couple transmitting information to East Germany is kept under surveillance. Nicholas Lyndhurst stars.
While Chapman (Nicholas Lyndhurst) is housing a defecting Russian, his wife (Serena Evans) is mistakenly abducted.
Spies recruit an unwitting electronics lecturer (Nicholas Lyndhurst).