The lead characters are ex-astronaut Jeff Tracy, founder of International Rescue, and his five adult sons, who pilot the organisation's main vehicles: the Thunderbird machines.
In 1967, Century 21 released an audio adaptation of "The Impostors" on EP record (International Rescue, catalogue number MA 120), featuring narration by series voice cast member Shane Rimmer as Scott Tracy.
Apprised of the situation by John, who has been monitoring communications from space station Thunderbird 5, Jeff refuses to order a rescue, knowing that Tracy Island will be exposed once Hale completes the repairs.
[3] In her autobiography, Sylvia Anderson, who voiced Ma Tuttle, commented that the episode makes good use of "space age" themes that were topical for the 1960s.
[4] Rating "The Impostors" three out of five, Tom Fox of Starburst magazine characterises the episode as a mixture of serious and light-hearted moments, describing the story as "eventually engaging".
[6] According to Richard Farrell, the episode derives humour from mocking the military and the news media (neither of which can locate International Rescue, despite being quick to condemn them) as well as poking fun at British and American cultural differences (for example, Penelope's ineptitude versus the Tuttles' initiative).
Noting that the Tuttles are capable and well equipped agents despite their "dozy hillbilly" ways, Farrell argues that they exemplify one of Gerry Anderson's "favourite themes" – the concept of people and things "not always being what they seem".
[7] Fran Pheasant-Kelly, an academic who has studied the series' depiction of social class, observes that the Tuttles' status as "impoverished Southerners" – conveyed by aspects such as Jeremiah's "rough appearance" and actor Peter Dyneley's "drawling" voice for the character – belies their reliability and resourcefulness in coming to Penelope and Parker's aid.
According to Pheasant-Kelley: "Given the obvious class differences between Penelope and the hillbilly couple, Anderson is clearly making a point about stereotypes in relation to social status.