For generations of people, the work of Gerry Anderson and AP Films / Century 21 are an irrevocable part of their childhood. For my part, I grew up during their big ’90s revival — the era of Anthea Turner’s make of Tracy Island on Blue Peter (though as no one in my family is particularly crafty (as it were) I had a Proper One), etc — so memories of Stingray, Captain Scarlet, Joe 90, and, most of all (of course), Thunderbirds are (more or less) as much a defining part of my childhood as they are for kids who grew up during their original airings in the ’60s. This documentary about the behind-the-scenes story of those iconic shows is an absolute nostalgia-fest, then; but it’s also more than that: a story of British endeavour, ambition and inventiveness, which perfected an art form and, in the process, revolutionised television and film. And all by a bunch of young Brits working out of a poky little industrial unit in Slough to make children’s TV programmes using puppets.

You may balk at such a claim, understandably, which is partly why this documentary’s very existence is a delight. However implausible it may sound, this gaggle of puppeteers were TV- and movie-making pioneers. For one thing, they were the first in Britain to spot the inevitable rise of colour TV, insisting Stingray be shot in colour (a full five years before ITV actually offered a colour service) to futureproof it, sales-wise. For another, their desire for realism and authenticity helped push forward the development of special effects. For various reasons they ended up making mostly sci-fi shows, laden with high-tech vehicles that were inevitably involved in exciting action sequences, requiring plenty of things like explosions and water — tricky to realise with models, but they did it anyway, and made it work too, and became experts in the field.

And finally (for this summary, at least), Anderson’s ever-present desire for realism led him to invent an aid system to aid his puppeteers. In order to control the puppets, the operators were positioned above the sets, afforded only a bird’s eye view — a hard position from which to make them perform well, considering they couldn’t see what they were actually doing as it appeared on camera. So Anderson devised a way for a video feed to be run from the film camera up to a TV monitor for the puppeteers. The process also meant the director and cinematographer could see exactly what the camera saw, including the ability to rewind and review footage, meaning that, if there was a worry about a mistake, it was no longer necessary to either wait for the film to be developed or shoot another take just in case. This system, if you aren’t familiar with it, is known as video assist and is an industry standard on film shoots (digital filming removes the need for it, of course, but that’s a very recent development).

Director Stephen La Rivière, from whose book this film is ‘adapted’, conveys these facts (and more) in amongst the narrative of the making of the programmes themselves. It’s a very well constructed documentary: smoothly told, never flagging, integrating what could be total asides as if they were a natural part of the story. Many key players are interviewed afresh, with archive interviews fill in for others (including Anderson, who passed away in 2012), meaning we’re getting the story firsthand. The result is full of admiration and respect for what was achieved by these iconic series, but isn’t adverse to revealing some of the truth behind their making.

For instance: for all his achievements in the field, Anderson never actually wanted to work with puppets — as a burgeoning TV production company desperate for work in the ’50s, AP Films were approached by a writer to produce a puppet series, so they did; that led to her commissioning another; they thought they could do better work by themselves, so they did; and it continued to spiral from there. Anderson constantly pushed for the puppets to be better — for their movements to be more realistic, for their lip-sync to be genuinely synced (again, innovating new technology to achieve this), for their proportions to be like humans rather than caricatures. But these advances eventually went too far, at times angering the puppeteers. They didn’t approve of the realistically-scaled puppet heads featured from Captain Scarlet onwards — they were harder to puppeteer convincingly, divorced of the margin of error that bigger heads allowed (and, arguably, needed); and they removed the puppet-ness of the puppets.

This culminated in Century 21’s final puppet series, The Secret Service, where all the scenes of people walking, driving, and so on, were performed by real humans in real locations with real props, while all the close-ups remained puppets. Many considered it ridiculous. Subsequently, Anderson was distracted into the world of moviemaking (with the flop Doppelgänger (now commonly known as Journey to the Far Side of the Sun)) and live-action TV (with UFO, for starters), and the puppet side of the business was violently shut down — an era-defining magic factory, dismantled with sledgehammers and thrown in a skip. Oh for hindsight, eh?

I’ve wound up telling interesting stories of Anderson & co rather than really reviewing Filmed in Supermarionation per se, but that’s because it’s an interesting story and the film tells it so very well (better than me. Oops.) For anyone who grew up with these programmes, this is an insightful, informative tribute to their ingenuity and quality. If you’re not familiar with them — if you don’t feel that ineffable childhood affection — I guess it doesn’t offer quite as much. Nonetheless, it remains the story of an incredible, pioneering endeavour that helped put the quality of British filmmaking on the map. It’s fun to think that, at a time when British culture was conquering the world and breaking new ground, through the likes of the grand extravagance of the James Bond movies and the subversive brilliance of the Beatles, standing toe to toe with them were a bunch of people in a tin shed with some puppets.

The UK TV premiere of Filmed in Supermarionation is on Sky Arts tonight at 9pm.