Widely regarded as the Andersons' most popular and commercially successful series, Thunderbirds has been praised for its special effects, directed by Derek Meddings, and its musical score by Barry Gray.

For missions involving undercover work, the organisation incorporates a network of field agents led by English aristocrat Lady Penelope Creighton-Ward and her butler Aloysius Parker.

[22][Note 3] Based in a temple in Malaysia, and possessing powers of hypnosis and dark magic, The Hood exerts telepathic control over Kyrano, his estranged half-brother, and manipulates the Tracys into rescues that unfold according to his own designs.

Lacking the means to drill an escape shaft, the authorities were forced to requisition a heavy-duty bore from Bremen, more than 80 miles (130 km) away, and transport it to Lengede by train, in a journey that took eight hours.

[35] During the characterisation and casting process, the Andersons' top priority was to give the series transatlantic appeal, increasing the chances of securing a US network deal and the larger audiences that the American market had to offer.

[38] Conscious of Cold War political sensitivities and not wanting to "perpetuate the idea that Russia was the enemy with a whole generation of children watching", Gerry Anderson decided that The Hood (voiced by Barrett) should be Asian and placed his temple hideout in Malaysia to defy viewer expectations.

[57] Jeff Tracy was modelled on Lorne Greene,[30][60] Scott on Sean Connery,[57][58] Alan on Robert Reed,[60] John on Adam Faith and Charlton Heston,[66][67] Brains on Anthony Perkins[56] and Parker on Ben Warriss.

[86][66] Dynamic shots could also be eliminated altogether: in an interview with New Scientist, director of photography John Read discussed the advantages of bypassing the puppets' lack of agility – so that they "appear, for example, to walk through doors (although the control wires make this impossible) or pick up a coffee cup (although their fingers are not in fact jointed).

[90] According to Sylvia Anderson, art director Bob Bell's challenge was to produce complex interiors on a limited budget while resisting the effects team's push for "more extravagant" design.

[91] While designing the Creighton-Ward Mansion sets, Bell and his team strove for authenticity, ordering miniature Tudor-style paintings, 1⁄3-scale Georgian- and Regency-style furniture, and carpeting in the shape of a polar bear skin.

[110][109] Another of Meddings' inventions was a closed, cyclical effects stage nicknamed the "rolling road": consisting of two or more loops of canvas running at different speeds, this device allowed shots of moving vehicles to be filmed on a static set to make efficient use of the limited studio space.

In return for its cooperation, the company asked APF to add a miniature Spirit of Ecstasy and ensure that character dialogue refer to the car's make by its full name, "Rolls-Royce", not the abbreviation "Rolls".

[131][138] Critic David Garland suggests that the challenge facing the effects department was to strike a balance between the "conventional science fiction imperative of the 'futuristic'" and the "seeping hyper-realist concerns mandated by the Andersons' approach to the puppets".

[143] John Peel describes this as "ostensibly a return to the 'series stars' concept long known in TV"; Garland states that the imagery demonstrates Anderson's commitment to "incremental realism" through convergence of human and puppet characteristics.

[146] According to Daniel O'Brien, author of SF:UK: How British Science Fiction Changed the World, the title sequence encapsulates the reasons behind Thunderbirds' enduring popularity.

On viewing the finished pilot, "Trapped in the Sky", Grade was so impressed with the series that he told Anderson to extend each episode from 25 to 50 minutes – long enough to fill a one-hour commercial timeslot.

[19][167] Tony Barwick, who had impressed Pattillo and the Andersons with an unsubmitted script he had written for Danger Man, was recruited to assist in writing subplots and filler material to lengthen the episodes.

and "The Cham-Cham" – had overspent their budgets, Pattillo lowered the finale's costs by writing it as a clip show, dominated by flashbacks to the series' early episodes and comprising just 17 minutes of new material.

Instructed by Gerry to give the opening theme a "military feel", Gray produced a brass-heavy instrumental called "The Thunderbirds March", recorded in December 1964 at London's Olympic Studios.

[185] Morag Reavley of BBC Online argues that the piece is "up there [...] in the quintessential soundtrack of the Sixties" along with the James Bond films and the songs of Frank Sinatra, Elvis and The Beatles.

[30][191] Internationally, the series has also been broadcast by TechTV, G4, Family Room HD and MeTV Toons (US), BBC Kids and YTV (Canada), Nine Network and Foxtel (Australia), TV3 (New Zealand), MediaCorp TV12 (Singapore) and RTÉ Two (Ireland).

[249] During a 2001 exhibition dedicated to the series, Masaaki Hirakata, curator at the Tokyo Metropolitan Museum of Photography, described Thunderbirds as "a modern sci-fi expression of bunraku, which probably explains why it was accepted so readily [in Japan]".

[250] Noting the technical detail of the launch sequences, Jonathan Bignell argues that the large amount of screen time given to the Thunderbird machines was partly motivated by the need to compensate for the puppets' limited mobility.

[147] In 2009, Warren Ellis argued that Thunderbirds' technological predictions could inspire "a generation of mad and frightening engineers", adding that the series "trades in vast, demented concepts [...] immense and very beautiful ideas as solutions to problems.

"[34] He believes that the series adhered more closely to cultural norms when subscribing to the "Cold War cult of the secret agent whose skills defend the home from enemies unknown".

Despite identifying examples in 26 out of 32 episodes, Kate Hunt of the University of Glasgow concluded that Thunderbirds does not actively promote smoking – a view opposed by the Roy Castle Lung Cancer Foundation when the series was re-launched on BBC2 in the 2000s.

[259][260] The Thunderbirds strip in TV Century 21 (later TV21) ran from January 1966 to June 1970; it was originally written by Alan Fennell and drawn by Frank Bellamy, with subsequent contributors including Scott Goodall and John Cooper.

[288] Devised as a comedy, Turbocharged Thunderbirds moved the action to the planet "Thunder-World" and combined the original puppet footage with live-action scenes featuring a pair of human teenagers.

[294][295] After Anderson's death in December 2012, the following year it was confirmed that ITV Studios and Pukeko Pictures had struck a deal to remake Thunderbirds using a combination of CGI and live-action model sets.

[318] Additionally, the Emirates Air Line cable car featured "Thunderbirds Are Go" branding and the InterContinental London–The O2 Hotel offered a "Lady Penelope afternoon tea" in September and October.