‘The genesis of the Cybermen.’ Series 10 is a strange mix of back-to-basics family viewing and some of the darkest material the show’s dabbled with. From space woodlice to existential doom and mass suicide then back to steampunk Ice Warriors. To some extent that’s always been the case, like the velvet darkness of Hinchcliffe after the tartrazine fizz of Pertwee, but it’s usually been through gradual transition rather than this pick n mix.

World Enough and Time is pretty much the bleakest the show ever gets. It’s as dark as anything Eric Saward ever wrote, leaning into the full body horror implications of the Cybermen. Rachel Talalay gets the aesthetics spot on: the gloomy, 1950s style hospital packed with bagged patients begging for death. The worst thing of all is watching Bill horribly injured, medically tortured, tormented by the Doctor’s instruction to wait for him, and then seeing him fail as she’s converted into a Cyberman – and not even one of the cool space robots, but the horribly compromised walking iron lungs of the Mondas versions. At least Adric went out with a bang: Bill’s death is protracted and appalling, and, thanks to Mackie’s performance, actually upsetting.

Which is the point: to show the full horror of Cyber-conversion. YMMV on whether this was necessary or not, given both The Age of Steel and Death in Heaven leant heavily into these ideas, but it’s certainly effective. More widely, I get the sense this is Moffat channelling the Davison years, his favourite run of the classic series. So, we get the strong sci-fi idea of the colony ship caught in the gravity of a black hole, causing huge time dilation issues; a Cyber-related companion death, and the Master in a bizarrely unnecessary disguise (was Harold Saxon well known on Mondas?).

Bringing back the Master at the point when Missy has started to rehabilitate is a great move. Gomez is fantastic in the opening scenes, mucking about until suddenly the situation becomes critical, when she and the Doctor are on the same page and really selling the idea that she was his first friend. I love the turn-the-tables moment when the Master gets to do to her what she did to the Doctor at the end of Dark Water. Simm has to spend most of the episode under heavy make-up doing a funny voice, which for a certain class of person makes him seem almost exactly like Zathras from Babylon 5.

Between all this, Capaldi is mostly there to react in shock. The episode opens with a flashforward to his imminent regeneration, a reminder where the story is heading. But after that he’s flitting around the edges while Missy and Bill carry the plot. Like many regeneration stories, the crisis is partly rooted in the Doctor’s own hubris. He’s got careless about unleashing Missy; he’s too reliant on speeches rather than action (when they don’t work, Bill gets shot), and he wastes valuable time – years from Bill’s perspective – giving a show-off university lecture about the temporal effects of gravity. Bill’s blood is on his hands. He’s lost the right to call himself Dr Who. They should have called this one The Doctor Fails.

Next Time: The Doctor Falls