Again, it’s not exactly moving at top speed, but there’s a steady sense of progress and development, with a couple of great surprises. The first is when Stott is revealed to be neither dead nor villainous. Previous episodes have clued us in that this is another Agatha Christie in Space thriller, and any Christie fan will know never to believe someone is dead when there’s no body. It’s also very Christie-ish to reveal that, far from being the drug smuggler behind this all, in fact Stott is a major in the Space Corps investigating a new source of vrax on the planet Eden.

The second surprise is that new source of vrax: the desiccated corpses of Mandrels. Baker and Martin like to give their monsters a twist (the beautiful Axons are actually tentacled monsters; the Mutts are actually part of the Solonian metamorphosis), and so making the Mandrels not just beasts, but beasts endangered by human greed, is inspired (and makes them the pangolins of the 22nd Century). What a shame, then, that Alan Bromly’s direction is again so unflattering. The Mandrel stalking the Doctor and Romana through the Eden jungle looks great: eyes glowing in the dark. The one that attacks the Doctor in the power room, zip visible, pants splitting as it falls, is shameful.

The Mandrels ae only one threat, albeit the main one this episode as they menace the Doctor and Romana, attack an annoying passenger and kill pop star Richard Barnes! Fortunately, Michael Craze’s brother is on hand, dressed like he’s fresh from a Village People tribute, as excise man Costa (he even makes a coffee). I do like the way Baker adds in various, credible perils for the Doctor: Rigg, an ally reduced to a pathetic junkie (laughing at the slaughter: ‘they’re only economy class, what’s all the fuss about?’); the bureaucrats who ‘just exist to tangle people up, wrap them round and round in red tape until they can’t move’, and the demat machine built to separate the merged ships. This leads into another excellent cliffhanger, as the Doctor is caught in the dematerialisation, and, thanks to the wonder of video effects, dissolves. The first cliffhanger of The Leisure Hive receives praise as if it’s a vast leap forward in the show’s visual effects. But for my money, this is at least as effective, and less contrived.

Next episode: Nightmare of Eden – Part Four