This episode is built around Tom Baker’s performance as Meglos: not the Doctor possessed, as in The Invisible Enemy, or playing evil, like in The Invasion of Time, but a villain wearing his body. He’s great: no twinkle in his eyes, the toothy smile entirely fake, persistently on the verge of snapping and killing the foolish Tigellans that stand between him and the dodecahedron. He manipulates Zastor’s trust and Lexa’s faith, assessing them coldly with that gimlet stare. And once he’s stolen the dodecahedron and begins reverting to his cactus form, he’s largely kept in the shadows – which makes the spiny makeup look quite disturbing.

The rest of the episode can’t possibly live up to this, and it doesn’t. The Doctor and Romana are largely stuck in the ‘chronic hysteresis’ and have to perform their way out of it, slightly implausibly. When they finally arrive on Tigella (Romana having changed into a flouncy velvet and lace number), the direction suddenly goes 80s pop video, with Romana creeping round a jungle set that doesn’t quite look as impressive as the one on Chloris last year before she gets caught by the space pirates.

Meanwhile, the Doctor makes his way to the Tigellan city where he’s immediately accused of stealing the dodecahedron. It’s all incredibly straightforward and – for a story with a time loop – linear. The fancy direction of The Leisure Hive might have been better suited to this, given how thin the material is, whereas The Leisure Hive might have benefited from being shot in a less distracting way. At least The Creature from the Pit had some jokes. The best we get here is ‘I… Swear allegiance to Ti?’ Edward Underdown hasn’t improved: his expressionless delivery of the line, ‘I’m Zastor, now the Tigellan leader’ plumbs new depths of half-botheredness.

Next episode: Meglos – Part Three