There’s a moment in An Adventure in Space and Time which shows Heather Hartnell visiting the Doctor Who set in 1964. As she walks in, she bumps into two Menoptra, sneaking out for a quick fag or something. Just for a beat, she clocks the bizarreness of it all as the two butterfly creatures walk past. It’s a second or two of pure WTF.

That’s fitting because The Web Planet is a six episode exercise in WTF. It comes from a production team wanting to jolt its viewers out of the everyday. They recognised that even after just a year and a half, Doctor Who had fallen into a predictable pattern of tea-time adventure and it was time to try something really bizarre.

This bizarreness doesn’t end with creating a world full of giant ants, giant butterflies, giant millipedes or even a tossed salad of them all (as if that wouldn’t be enough). It stretches to production decisions which deliberately alienate the viewer, such as blurring the camera lens, having a soundtrack of experimental electronica and dialogue peppered with strange alien speech patterns. This is a story that wants you to see and hear Doctor Who in a new way. (Or it’s a story which wants to assault your eardrums while obscuring your view of what’s going on. Potato, potahto).

Its ramshackle production values, its sleepy pacing and its chirruping soundtrack make The Web Planet almost unwatchable to a modern audience. And yet by several measures, it has proven to be a phenomenally successful Doctor Who story. Made in the height of Dalekmania, it outrated the Daleks, averaging 12.5m viewers. Selected to be one of the first Doctor Who novels, its print version has been read by millions of people. It gets name-checked in modern Who and mentioned by Who luminaries like Peter Capaldi as one of their most potent memories of the show. It’s an enduring triumph of ideas over their plywood and poster paint execution.

It transcends all this because of its villain. It’s not a scheming human or a sly Sensorite. This is the Animus and it’s a malevolent force growing like cancer through the planet, poisoning its water, ravaging its landscape. It animates the otherwise docile creatures around it and turns them into killers. It’s strong enough to drag the TARDIS off course. It corrupts everything around it. There’s never been anything like it, before or since.

It gets a bit lost in the story’s ropey design work, but the Animus is a spider which has spread its web across the planet. This makes me think how this story came about. When thinking up a plot preposterous enough for Doctor Who, apparently writer Bill Strutton remembered a painful incident from his childhood, when he was bitten by a bull ant, at his home in Moonta, South Australia. Had young Strutton been bitten by one of Australia’s famously venomous spiders – a funnel-web or a redback – he would have died. You don’t mess with those mofos. Google images of a funnel-web’s web, and you’ll find an eerie looking whirlpool shaped web, leading to a dark centre and, well you can see what Strutton may have been thinking off.

Sadly, when we finally get to meet the Animus in this story’s final ep, it doesn’t look particularly spidery. It’s a dome half suspended from the ceiling, covered with tentacles of old vacuum cleaner hoses which spill out over the entire room. The actors do a good job of looking suitably horrified at it, but there’s no hiding that it’s afflicted by the same budgetary pressures which give us Zarbi which run into cameras and Operta with comical Rastafarian haircuts. The Doctor (William Hartnell) and Vicki (Maureen O’Brien) have to lie down and self-entangle themselves it in at one stage, signalling the brute’s limitations.

But wishing for a more technically sophisticated version of The Web Planet gets us nowhere (although if there was ever a candidate for an animated version of an existing story, here it is). And it neglects the elements which transcend its general tackiness. There’s that truly spooky cliffhanger to its fifth episode, with the Doctor and Vicki enveloped in web. But again, it’s the Animus which works, because of its creepy (crawly?) voice (Catherine Fleming). That calm, whispery cadence, like a sinister anaesthetist. (Funny how giant spiders in fiction are often female.)

If The Web Planet is “about” anything (and I’m not sure it is. It could be just so much sci-fi hokum), I think it’s about evil as a force of nature. Up until this point, Doctor Who’s monsters had backstories which explained how they got to be so wicked. Even the Daleks were originally survivors of war, twisted and transformed by xenophobia. The Animus has no backstory, short of just arriving one day to upend everything on Vortis. It just is. It’s just there. And it grows like a malignant tumour. There’s something both chilling and everyday about that.

Strutton was in a POW camp in WW2, so no doubt he saw the best and worst of human nature on display there. Perhaps the Animus is his stand-in for the Nazis, presiding over a microcosm of society, with the Zarbi as guards and the rest of this planet’s population as the oppressed prisoners. Unlike Terry Nation, who used the Daleks to question the basis of Nazism, Strutton’s not interested in how evil emerges. For him, it’s as natural as any other part of the world. But left unchecked, it will take over, like weeds strangling a garden.

Doctor Who never returned to The Web Planet, at least on TV. Despite it being the site of its greatest ratings success until 1974. As the Hartnell era ended, the show turned more and more to Earth-bound settings. Not just bases under siege and adventures with UNIT in the home counties; even alien planets had more humanoids and looked and felt more familiar than smeary, noisy Vortis. Never again would the series try to create such a completely alien world. Camera lenses remained undirtied. No more special “insect movement” choreography for the monsters. Return visits to Vortis were restricted first to TV Comic, and the books, audio dramas and give-a-show slide projectors, where the Zabi didn’t have legs like rugby players and Menoptra didn’t trip over their own wings.

It’s truly a world too broad and deep for the small screen. But that’s why it never gets forgotten. That’s why those Menoptra get a cameo with Heather Hartnell, why Margaret Slitheen’s afraid of venom grubs and why this shaky old runaround gained thousands of new fans when it aired on Twitch. We really can’t get enough WTF.

LINK TO The Underwater Menace: both shot at Riverside Studios. Can I get away with that?

NEXT TIME: Stand and deliver! We’re having quite the Knightmare in The Woman Who Lived.