The opening scene is almost exactly like the start of Spearhead from Space, but whereas Spearhead went on to establish the new series premise in a fairly realistic way, we’re now well into the Doctor Who version of Avengerland where everything is heightened. Hence Chinn, this story’s civil servant. Last season’s civil servants, like Geoffrey Palmers’ Masters, were played with a level of naturalism completely at odds with Peter Bathurst’s frankly ridiculous turn here. But when you’re introduced holding a file marked “top secret” in a massive cartoon font, I guess it sets the tone for your performance.

In part, I think the point of this episode is to be unsettlingly weird. Our first glimpse of the Axos spaceship shows something that looks like a dried fish filled with sprouting potatoes. Director Michael Ferguson plays a similar trick to the one he pulled off in The Ambassadors of Death, only even better, and makes the aliens seem truly unearthly. The inside of their ship vivid shades of gold and orange, with no straight lines, stepping through membranes, tendrils and gills. Electronic effects are used to suggest the potato monsters erupting from the walls, and to simulate the effect of Axos’ mental attack on the Doctor.

To a large extent, the episode would have failed if Axos hadn’t been overwhelmingly strange, because in no way is the story “realistic”. Apart from Chinn we get Pigbin Josh, one of the great WTF characters in Doctor Who, protractedly oo-arring his way to a grisly death. We’ve got Bill Filer, basically Felix Leiter but played by a Welsh actor, with a secret agent car radio that can listen in to UNIT. There’s a moment when the Doctor is introduced as UNIT’s scientific advisor and Professor Winser raises an eyebrow – undeservedly, because Pertwee’s actually the only person who seems to be playing this straight. Although why in the midst of a crisis the Doctor feels the need to change from his red jacket/purple cape combo to his blue jacket/red cape is anyone’s guess.

There’s lot that’s pretty ridiculous and cartoonish about this. But that’s slightly the point: to be more colourful and energetic than Season Seven. In time, this will be toned back down a bit, but in context it’s similar to the way Season 18 will over-compensate for Season 17’s supposed silliness. This is as in-your-face as Aliens of London, another story pushing to see how far it could go. Doctor Who would be a poorer show without episodes like these.

Next episode: The Claws of Axos – Episode Two