Trivia: The electric drills that Virgil and Alan use to plant the explosive are the WASP pistols from "Stingray".
Trivia: Apart from the first episode (which he had not been employed before voice recording commenced), this is the only other episode in which Matt Zimmerman does not part in.
Trivia: The Duchess (from the episode "The Duchess Assignment") makes two appearances in this episode. Not only is she in a photograph in Cass Carnaby's dressing room, she can be seen sitting among the audience during the performance of the Cass Carnaby Five.
Trivia: When Prescott is driving in his car on his way to the Hudson Building, look in the background and you can see a building with a large white Swastika on it.
The Duchess Assignment - S1-E21
Trivia: When Jeff is with Lady Penelope at the London Air Display, look in the background and you can see The Hood in his "Martian Invasion" disguise.
Trivia: When Warren Grafton and his cohorts are imprisoned at the end of the episode, you can see that one of his fellow prisoners is "Scobie" from the second season episode "Give or Take a Million".
The Duchess Assignment - S1-E21
Trivia: Lil, Lady Penelope's chef (seen in the episode "Vault of Death"), makes a cameo appearance in the gallery scene.
Trivia: This is the only episode in which the real Thunderbird 2 does not appear.
Trivia: When Tin-Tin is in the lounge of the Fireflash, look in the background and you can see the woman driver who started the Thompson Tower fire in the episode "City of Fire".
The Duchess Assignment - S1-E21
Trivia: The blonde-haired croupier on the Duchess of Royston's table in the casino at the beginning of the episode would go on to be the crook "Scobie" in the second season episode "Give or Take a Million".
Trivia: The Manor to Penelope's right at the Clydeside launching of "Ocean Pioneer II" is Professor Holden from "The Mighty Atom". Tony Williams (from "Cry Wolf"), MI5 agent Tidman (from "The Man from MI5") and Lovegrove (from "The Vault of Death") are also visible in the crowd, as well as the Commander of "Ocean Pioneer I".
Trivia: In the opening scene, you can see two characters who have appeared in previous episodes. First, when the TV reporter comes through the crowd with the cameraman, you can see Blanche Carter (from "City of Fire") in the background, and the photographer who takes a picture of the impostor is Colonel Tim Casey from "Edge of Impact".
Trivia: When the Hood is in the laboratory in the tracking station, the camera focuses on the tabletop and one of the items on the table is a photograph. This photo is of Eddie Houseman from the episode "End of the Road".
The Duchess Assignment - S1-E21
Trivia: At the art exhibition, look very carefully and you can see that one of the paintings is Virgil's portrait of Alan seen at the end of the episode "Move - And You're Dead".
Trivia: Lord Worden was originally seen as Sir Jeremy Hodge in the episode "The Perils of Penelope".
Terror in New York City - S1-E4
Trivia: When Scott contacts the Empire State Site Control in Thunderbird 1, look very carefully and you can see a small insect climbing up his seat.
Trivia: When Professor Holden is demonstrating The Mighty Atom to the other professors (including the Hood), look on the table and you can see the communicator (with an eagle on top of it) that Jeff Tracy uses at Tracy Island.
Trivia: The character who tries to unsuccessfully defuse a bomb in this episode is "Bob Meddings". This is a reference to the art director Bob Bell and Derek Meddings, the programme's special effects director.
Trivia: Although the pyramid people are named as "Zombites" in the script and the symbol on their helmets is a stylised "Z", they are never actually referred to as "Zombites" in the episode.
Trivia: This episode has the smallest guest cast of all the Thunderbirds episodes, with only two characters other than the regular cast.
