Thunderbirds – Extending The First Eleven

For those of you that don’t know, every week I have been writing in-depth reviews of each episode of the original Thunderbirds series. During these reviews I have been closely studying what appears on screen and highlighting bits and pieces which point to how the episode was produced, and which parts worked well or didn’t work so well. Part of that process has involved analysing one aspect in particular which relates to the first eleven episodes to go into production.

Part of the success of the Thunderbirds series is often attributed to the fact that each episode is 50 minutes long, filling an hour of television when combined with adverts. This gave the production team an opportunity to tell more complex stories and give the viewers more opportunities to get to know the characters.

This was not, however, always the way Thunderbirds was going to be. It started life in a half-hour format. The story of how that came to change is legendary. AP Films had already produced 9 episodes, with another 2 still in production when Gerry Anderson took the pilot episode, Trapped in the Sky, to Lew Grade for his approval. At the end of the showing, Grade reportedly jumped up, walked down the length of the theatre towards the screen, span on the spot and declared, “This is not a television series!” Gerry almost had a heart attack, concerned that the whole thing had been a complete failure. “This is a feature film!” And with that, Lew Grade insisted that every episode had to fill a one hour slot… even the episodes which had already been finished. They would need to be extended somehow, as would the scripts that were currently waiting to be shot.

The AP Films team were sent into overdrive. Scripts that were about to go into production needed to have more material written for them. Episodes that had already been completed needed to have new material written for them and then filmed, but production also couldn’t stop on new episodes. The solution was to produce additional material for the half-hour episodes alongside the shooting of new episodes. It would have been an incredibly busy time at the studio with everyone working their absolute hardest to cope with the enormous workload. Writer Tony Barwick was hired and worked alongside the script editor, Alan Pattillo, and under the supervision of Gerry & Sylvia Anderson to write filler material to extend the scripts.

It sounds mad to even consider going back to episodes shot months beforehand and attempting to add bits and pieces to them in a coherent way that also doesn’t stick out too badly as being a late addition. The question is, how did the writers and the production team do at pulling off this incredible task? The results were mixed, but for the most part they got away with it superbly well. If you didn’t know otherwise, you’d probably never pick up on the fact half of each episode was shot at a different time to the rest of the episode. When you look at them more closely the cracks start to show, but they really did do the best job of it that they could have possibly done.

Just to remind you which episodes needed to be extended after they were finished as half-hours, here they are with links to my full reviews of them:

  1. Trapped in the Sky
  2. Pit of Peril
  3. City of Fire
  4. Sun Probe
  5. The Uninvited
  6. The Mighty Atom
  7. Vault of Death
  8. Operation Crash-Dive
  9. Move – And You’re Dead
  10. Martian Invasion
  11. Brink of Disaster

operationcrash-dive00862In terms of adding material to the scripts, one of two methods was usually adopted depending on what could be done with the episode in question. Either the additional material was added in one solid lump – a big chunk which sat at the beginning, middle, or end of the half-hour to expand the story by adding a subplot focussing on certain characters or ideas. The most prominent examples include the second half of Operation Crash-Dive which sees International Rescue themselves flying the Fireflash and solving the sabotage mystery, or the first half of Pit of Peril which sees the army attempting to rescue the Sidewinder themselves. Generally speaking this approach was a little more hit and miss. The best examples are those that tried to expand International Rescue’s involvement in the story such as in Operation Crash-Dive or Martian Invasion.

The worst example would be those that barely feature International Rescue at all, such as  the subplot of Pit of Peril. It features characters that we don’t really care about pointlessly going down into the pit and getting horrifically burnt and achieving absolutely nothing, while International Rescue are just left sitting on standby. The same can be said of Bob Meddings’ attempt to save the Fireflash in Trapped in the Sky. If the subplot doesn’t end up achieving anything or changing the outcome of the episode, then it’s rather difficult to appreciate it. That is, of course, very difficult when you’re trying to add a subplot to an episode that already has a very firm conclusion like those particular episodes did. Trapped in the Sky and Pit of Peril were clearly very tightly written half-hour stories originally, and probably would have been better off being left that way.


themightyatom00519The Mighty Atom adds a subplot to the beginning of the episode as The Hood accidentally sabotages an irrigation plant in Australia before International Rescue had started operating. Although this subplot comes in one solid chunk at the beginning of the episode, and is essentially the same disaster that happens later, subtle changes have been made to ensure that the whole episode doesn’t repeat itself and that the events of the subplot do affect the main plot – The Hood’s destruction of the Saharan station is made to look like a result of the actions he took at the Australian plant. The technicians know how to act upon the disaster having experienced what happened in Australia. The whole thing is just tied together much more neatly, although unfortunately the addition of Lady Penelope to the episode was rather less neat. She tags along with Virgil but then has nothing to do during the rescue itself because that was an original part of the episode that didn’t involve her. So she doesn’t end up doing anything much at all.

The Uninvited takes a similar approach by starting out with the addition of the crash of Thunderbird 1, and Scott being found by Lindsey and Wilson in the middle of the desert. This gives the explorers and Scott a pre-existing relationship based on that experience which appears to change their dynamic when we come into the original part of the episode set in the pyramid. So although a large chunk has just been added to the beginning of the episode, it manages to form one whole story.

Other episodes take a slightly different approach with adding their subplots by weaving them into the episode piece by piece, rather than all in one go. A good example of this comes in City of Fire. The gas used by Scott and Virgil to cut through the doors and access the basement corridors is revealed to be experimental and has previously knocked Scott and Virgil unconscious during testing. In addition to this, the Firefly is also given a role in the rescue operation to clear a path for the Mole, something which wasn’t originally a part of the episode but makes perfect sense to include in the story. The result is additional material which doesn’t feel like it’s had to be forced into the story and builds upon the existing plot, rather than putting it on hold while something new is dealt with. Raising the stakes for International Rescue with the experimental gas also makes the audience more emotionally invested in Scott and Virgil risking their lives and thus learning more about the type of characters that they are.

sunprobe00250The same can be said of the additional material in Sun Probe which manages to weave in the subplot of Virgil and Brains taking the trasmitter truck to Mount Arkan to try and send a safety beam to the doomed Sun Probe rocket. They’re conveniently put in a position to save Alan, Scott, and Tin-Tin when they end up facing the same fate in the new ending to the episode. It builds upon the otherwise simplistic story of Thunderbird 3 chasing after the Sun Probe, transmitting the safety beam successfully, and that’s the end of the episode, and instead the story becomes about much more than that. The focus is placed firmly on the heroes of International Rescue, which is who we watch the show to see after all.

vaultofdeath00466Though not the most action-packed episode in the series, the hour-long version of Vault of Death has a plot that is so tight one can barely make out what was originally part of the story and what was added later. The original half-hour version, which presumably just focussed on International Rescue trying to get Lambert out of the vault, was transformed into something far more interesting with the added revelation of Parker’s back-story and his attempts to defend the honour of his comrade, Light-Fingered Fred. The subplot plugs into the main plot perfectly to the point that the rescue itself ends up blurring into the background, which some may consider detrimental to a show all about rescuing people.


Move – And You’re Dead becomes a lot less about rescuing Alan and Grandma from the bridge of San Miguel and more about how they got there in the first place. The rescue itself becomes a minor part of the story, which makes it less action-packed but does give the episode one of the most interesting and unique structures of any Thunderbirds episode because of the heavy use of flashbacks to tell the story.


Brink of Disaster also takes the ‘piece by piece’ approach to sprinkling its subplot throughout the episode, but fails to actually weave it in all that well and connect it to the main plot. What we’re left with is almost two seperate stories which play out in the same episode. You’re bound to connect with one of those stories more than the other, making a whole half of the episode less interesting by default. People either consider Brink of Disaster to be an episode about Jeff, Brains, Tin-Tin, and Warren Grafton travelling on a doomed monotrain, or to be an episode about Lady Penelope getting burgled; there isn’t much crossover between the two aside from the fact Grafton is behind both of them.

martianinvasion00784Perhaps the material added to the series which had the most potential was in the episode Martian Invasion as International Rescue chase down The Hood who has successfully captured footage of a rescue operation which was, to be honest, fairly unremarkable. It was the opportunity to have an epic showdown between The Hood and the Tracys. I get the impression that was the idea behind it. Unfortunately it didn’t quite play out that way. It’s a repetitive and slightly odd sequence which leans a little too far towards playing it for comedy by the end. I don’t think that’s entirely because the writers were lacking creativity. I think it’s because this sequence would have been one of the last that was shot for the first series, around the same time that the episodes Attack of the Alligators and The Cham-Cham were being shot, both of which went over their allotted budget. They essentially did what they could do with limited time and budget. It still comes out okay, but just not quite as good as the premise suggests it could have been.

So overall then I can hardly say that there’s a right or a wrong way to extend a half-hour Thunderbirds episode. I actually love that different approaches were taken depending on what could be done with the available resources. Generally speaking though the episodes that worked best for me were ones which tried to give us more of International Rescue in the added material, and did so by raising the stakes and putting them in danger or by generally lengthening their involvement in the episode. This puts episodes such as City of FireSun Probe, The Uninvited, Vault of Death, Operation Crash-Dive, and Move – And You’re Dead towards the top of my list. Trapped in the Sky and Pit of Peril are by far the weakest episodes to be given the extension treatment. They were clearly such tight and exciting half-hour stories that the writers had no option but to add material which could not alter the outcome of the episode in any way, making the sequences fairly pointless and a bit boring.

In terms of how the filming of the additional material was handled, and how well it matches on screen to the original episode, it depends how closely you’re watching basically. To a first time viewer, most of the continuity issues might go unnoticed. Your brain might detect that something has changed but it might not be clear exactly what that is. It’s only when you know the episodes, and particularly the faces of the puppets, inside out that it becomes clear where the joins are.

Different puppet stages at the studios used different sets of puppets which attempted to replicate the main characters. These replicas were close to being identical, but not quite there. In an episode with material shot months apart, quite often the puppets will suddenly look slightly different and that’s how you can tell what’s original material and what was shot later with a different puppet. Here are a few examples:

On the left is Scott from the original half-hour version of Martian Invasion, and on the right everything in the scene is more or less the same, except that Scott’s head is noticeably different as we transition into additional material.

In Operation Crash-Dive the transition into additional material is clear by looking at Jeff and Gordon’s faces in particular.

A similar change happens with Jeff in a scene quickly added before Thunderbird 3 launches in The Uninvited.

There are also various other continuity errors which clearly demonstrate where additions have been made. The list of those is as long as your arm, but indicators include things like the ‘H.F.C’ label appearing and disappearing on Thunderbird 1’s control panel.

The International Rescue hats were also generally used more towards the beginning of the production and then dropped when it was probably realised that they looked a bit silly, so you’ll notice that additional material tends not to feature the hats quite so much as the original parts of the episodes.

On a scripting level, another indicator of added material is the appearance of, or references to, Grandma Tracy in episodes prior to Move – And You’re Dead, namely Sun ProbeThe Uninvited, The Mighty AtomVault of Death, and Operation Crash-Dive. It seems highly likely that Move – And You’re Dead was supposed to be the episode that introduced her good and proper to the series as her first appearance, but this fact was somehow forgotten when the writers were adding to prior episodes. The broadcast order fails to correct that by moving it all the way to episode 20, rather than episode 4.

Speaking of the broadcast order, this was somewhat affected by when episodes were totally completed. This is why episodes such as Martian Invasion which were being extended at the end of the first series, were also broadcast towards the end of the first series.


As The Perils of Penelope and Terror in New York City were the first hour-long episodes to be completed, they were moved to the beginning of the run while Trapped in the Sky and Pit of Peril would have had to be extended in quite a hurry to keep their place as the first two episodes to be broadcast. Most of the extended episodes then form a block in the middle of the series which is roughly when additional material for them would have been shot. Then Move – And You’re DeadMartian Invasion, and Brink of Disaster move towards the end of the first series, and were extended around the same time as the episodes which surround them in the broadcast order such as The Duchess Assignment and Attack of the Alligators!.

There are, of course, a great number of other indicators and tell-tale signs that a scene was filmed later for the first eleven episodes, but we’ve covered the main ones. To learn more about the process, take a look at my reviews of the episodes in question.

Leave me a comment about your thoughts on the work done to extend episodes 1-11, how well do you think AP Films pulled it off?

6 thoughts on “Thunderbirds – Extending The First Eleven

  1. This must have been an absolute herculean task for such a small company but also a very exciting time, I, like you have trouble with eps 1 & 2, there pacing with the added material is painful slow sometimes & you just want to hit the FF button.. Being a long time Anderson & Thunderbirds fan, I’d just like to congratulate you on a fascinating article, & the fact that you’ve made me want to go back now & want to study the episodes & spot the additions myself. Thank you…


  2. Another fascinating and meticulously-researched post – well done! I’ve been re-watching the series over the past few weeks, and your posts have made such an excellent companion.
    I agree with most of what you say – although I do personally feel Brink of Disaster actually works quite well.
    I agree Pit of Peril seems to drag a bit – for a long while though I actually thought it was episode 1 (after I missed the repeat of Trapped in the Sky the previous week, which started a UK re-run of the show in the 80s).
    Like you though, I feel they did an excellent job all-round of extending the episodes, and never would have spotted any of the continuity stuff unless you’d pointed it out to me! 😉


  3. I’ve always wondered what might have been added to the early episodes to extend them to 50 minutes. This article is a great account of what the possible footage was. The 50 Years of Thunderbirds magazine features details by Chris Bentley mentions what footage was added to make the episodes longer. I wonder what might have been added to the episodes that had been scripted and needed to be extended?

    The Perils of Penelope: The Sun Probe launch at the beginning of the episode, hence why they are the only two consecutive linked episodes in the series.

    Terror in New York City: The oil fire at the start of the episode.

    End of the Road: Eddie Houseman visiting Tracy Island and the subsequent dilemma.

    Day of Disaster: Brains in England at the time of the disaster.

    Edge of Impact: Colonel Tim Casey visiting the island and the subsequent dilemma (again).

    Desperate Intruder: Brains and Tin-Tin diving to the bottom of the lake.

    30 Minutes After Noon: The first part of the episode with the Hudson Building fire and perhaps, the Erdman gang being told how to get past the robot guards.

    The Impostors: ?

    The Man from MI.5: Maybe the theft of the nuclear plans?

    Cry Wolf: The Williams boys visiting Tracy Island.

    Dange at Ocean Deep: The communication blackouts.

    The Duchess Assignment: ?

    Attack of the Alligators!: Alan fixing the Tracy Island aerial mast.

    The Cham-Cham: ?

    As we know, Security Hazard was written as a money saving episode consisting of flashbacks to Trapped in the Sky, Sun Probe, End and Day, since these had been originally filmed or scripted as 25 minute episodes.

    Anyone else care to make any ideas on added material?

    Liked by 1 person

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