‘I’m supposed to be working against him.’ This is a hot mess. Two episodes ago, Mawdryn declared he was going to be a Time Lord, now he just wants to die. Turlough is meant to be assassinating the Doctor, but now the Black Guardian’s complaining he isn’t following the Doctor’s orders. Mawdryn’s mutation is now, somehow, a time travel virus. It’s difficult to imagine anything quite so spotty going out under any other established production team.

Over and above these inconsistencies, I do not like the handling of the Doctor’s self-sacrifice. The scene is written and played as if the Brigadier, Tegan and Nyssa bully him into killing his own future to save their skins. The easy fix would have been for them to object to the Doctor giving in to Mawdryn’s blackmail, and the Doctor overruling them. Instead, he seems to reluctantly give in to their accusing stares. Meanwhile, Turlough’s still wandering about the ship’s corridors disconnected from the rest of the story. The Black Guardian backed the wrong companion: Nyssa and Tegan are better at killing the Doctor. I like that Tegan takes a moment, after the fireworks, to thank the Doctor, but it wasn’t enough for me.

The flipside: I think the end is great. Grimwade directed Earthshock, and does more in the final scene to address the fall-out than anyone else. For a moment, it looks like the Doctor’s left another boy trapped, alone, on a spaceship about to explode. Cue a mad dash back into the TARDIS – where Turlough is already safe. This neatly establishes why the Doctor is so ready to accept Turlough as a companion (Nyssa and Tegan look less convinced): to make amends for Adric.

Look at the Doctor and Turlough’s easy interactions through the story, so different from the tension with Adric (who wasn’t meant to be killing the Doctor); look at the way the Doctor seems to enjoy answering Turlough’s questions. I confess, Turlough’s my favourite Davison companion; the one I think works best, because the Doctor’s always trying to make him something better, and Turlough, despite himself, wants to live up to those expectations. I might not think much of Mawdryn Undead, but it was worth it for Turlough.

Next episode: Terminus