‘Good luck Adric.’ Earthshock is unforgettable for that ending, which I think it earns. I’ve pointed out a lot of things I don’t like, or think don’t work, about the story, but it does a good job of escalating the stakes, creating mounting chaos, and setting up the context for Adric’s death. There are a few contrivances (the Cybermen have to become sadists so that Adric is forced to remain alive on the bridge rather than going back to the TARDIS or being shot), but most of them tie into ideas introduced in earlier episodes – like the Cyber Leader’s desire to make the Doctor suffer – or plot points, like the death of the dinosaurs and the damage to the TARDIS console. Only the freighter’s surprise time travel feels inadequately set up.

The lead up to the death scene is a flurry of moments that seem to offer hope, then snatch it way. Scott storms the bridge and rescues the hostages, but then Adric rushes back to try to save the Earth. Adric seems to have got the answer – then, in a beautifully framed shot, a dying Cyberman blasts the controls. The Doctor regains control of the TARDIS, but there’s another Cyberman. It’s fairly nail-biting. The final shot of Adric is haunting. He’s not even wearing his badge, but clutching his brother’s belt – in the end, all that genius is irrelevant. He’s just a frightened boy dying alone while trying to do the right thing.

Inadvertently, Earthshock also shows why one of the companions had to go: without enough plot for three of them, none of them gets anything useful to do. Adric spends most of the episode standing watching the Doctor. Tegan gets caught, threatened, hysterical and useless. Nyssa doesn’t even leave the TARDIS, watching it all with Kyle like they’re doing a Behind the Sofa commentary.

Davison gets a couple of good lines (‘You would be very crumpled,’ he tells the Cyber Leader), although Saward’s version of the Doctor remains largely ineffectual. He claims emotions and friendship are important, but nothing in the story backs up this assertion. Just as in Saward’s previous script, he ends up accidentally creating history, and watching in pained helplessness at the consequences. Had the fourth Doctor lost a companion it would have been a game changer. Here, it just ties into a theme of the fifth Doctor being a bit hapless.

At least Saward writes the Cybermen with relish. Post 9/11 the Cyber Leader’s plan, and his declaration of ‘a great, psychological victory’ disturbingly marks this lot out as terrorists. They look great striding round the darkened hold of the freighter accompanied by Malcolm Clarke’s strikingly different music. This is a great comeback for them, and a great exit for Adric. For the Doctor, and the show, it’s a more mixed story. A lot depends on what comes next.

Next episode: Time-Flight