Enemy saboteurs infiltrate the industrial suburbs of London, aiming to disable three power stations in the city and five others strategically located throughout the UK. Their goal is to cripple the British economy and allow subversive forces to gain influence within the government. However, the saboteurs are thwarted not by counterintelligence agents, but by ordinary London police officers. Cast: - Liam Redmond as Commander Robert Brennan - André Morell as Superintendent Folland - Anthony Bushell as Major Elliott - Kenneth Griffith as Jimmy Ellis (Soviet agent) - Patric Doonan as George Ellis - Joan Hickson as Mrs. Ellis - Anthony Nicholls as Sir Grant Mansfield, M.P. (Head Soviet agent, and putative Prime Minister) - Mary Morris as Anna Braun (Soviet agent) - Geoffrey Keen as Morgan Williams (Soviet agent) - Stuart Lindsell as Commissioner - John Bailey as Stringer - Dora Bryan as Mrs. Bowers - Charles Lloyd-Pack as Percy Ward - Laurence Naismith as Reginald Gordon-Wells Runtime: 90 minutes