- "My, this is a deserted area. One just wouldn't know where one was, would one?"
— "Gayle Williams"
The British government asks for International Rescue's help in locating the missing blueprints for an atomic weapon. Whilst tracking the culprits, Lady Penelope is kidnapped and held aboard a bomb-rigged boat. Scott and Gordon have very little time to rescue Penelope and steal back the plans before the bomb explodes and the villains escape.
- Main article: The Man From MI.5/Storyline
- Main article: The Man From MI.5/Transcript
- Jeff Tracy - Peter Dyneley
- Scott Tracy - Shane Rimmer
- Lady Penelope Creighton-Ward - Sylvia Anderson
- Virgil Tracy - David Holliday
- Alan Tracy - Matt Zimmerman
- Brains - David Graham
- Parker - David Graham
- Tin-Tin Kyrano - Christine Finn
- Gordon Tracy - David Graham
- John Tracy - Ray Barrett
- Jimmy Bondson - Ray Barrett
- Carl - David Graham
- Ritter - Ray Barrett
- The Third Man - Matt Zimmerman
- MI.5 Agent Tidman - David Graham
- Fireflash Stewardess (not seen on screen - voice only) - Christine Finn
- Captain Blacker
- Fireflash Passengers
International Rescue Equipment UsedEdit
- Thunderbird 1
- Thunderbird 2 (Pod 4 containing Thunderbird 4)
- Thunderbird 4 (Harpoon drill with knock-out gas)
- Thunderbird 5
- FAB 1
- FAB 2
Non-International Rescue Equipment UsedEdit
- First Appearance: FAB 2.
- The model submarine Brains used for his experiment in the Tracy villa pool was also used as The Hood's 3E Submarine in Desperate Intruder. It even still has 3E written on the sides.
- When broadcast in the half-hour 'cliffhanger' format, part one concluded with Carl taking off in his boat from FAB 2 with Lady Penelope as prisoner.
- The backdrop used for the harbour scenes also appears in the opening scene of The Duchess Assignment, in the Captain Scarlet and the Mysterons episode Model Spy, and in the Joe 90 episode The Race.
- This episode features the first full Thunderbird 4 launch sequence shown from inside Pod 4 prior to this, Thunderbird 4 had only been seen emerging down the ramp outside the pod door. This is also the only occasion in which Thunderbird 2 gently rests the pod on the surface of the water and then rises clear of the pod with lifting jets (normally, the pod is simply dropped onto the water).
- Main article: The Man From MI.5/Goofs
- French: L'homme du M I5
- German: Der Mann vom M.I.5
- Spanish: El Hombre del MI.5; El agente MI5 (DVD)
- Italian: S.O.S. Servizi Segreti Britannici
- Dutch: De geheime agent (TV); De man van MI. 5 (VHS, DVD)
- Japanese: 情報員MI. 5