‘A bit crude but immensely satisfying.’ Being cold about it, this ending isn’t quite as good as the set-up. Partly it’s that the execution isn’t quite snappy enough so some of the repartee doesn’t sizzle as much as it might, and the Mentiads’ destruction of Zanak’s engines looks fairly drippy. Mainly it’s because, having criticised Xanxia’s bafflegab the Doctor spouts a great deal of it himself, and Adams doesn’t quite give the villains the exits they deserve (Xanxia, in particular, literally just fades away).

On the other hand, the set-up has been as good as Doctor Who gets, and it’s not exactly a crashing come down. It’s still immensely likeable and witty, packed with clever ideas and nice twists. The reveal that the Nurse is actually the tyrant queen is great, and I love the Captain’s weary little sigh as she nags him, and the fact that he stops shouting and blustering here, now he no longer has to play the villain. Similarly great: the reveal that the Captain has been plotting against her all along, and that his plan only fails because the planet Calufrax is, in fact, the second segment of the Key of Time. Bruce Purchase’s performance is marvellous: his poignant clutching of the late Mr Fibuli’s specs (‘He was a good man’) is even more touching than the Graff’s eulogy for Sholakh.

So on balance, this is one of the highlights of the series. In a moment when I imagine every TV studio was wondering how on earth they produce sci-fi in a post-Star Wars world, Season 16 is already offering two convincing solutions. The Ribos Operation took George Lucas’ story of a backwater planet in a lived-in universe populated with recognisable “types”, and where a lot of the story is noises off. Adams picks on the big ideas, and humorously subverts them: a planet-sized weapon is defeated by a spanner; the cyborg villain turns out to have been the hero all along (was George Lucas watching this?). Both approaches end up being more successful and interesting than anything on offer the previous year (and I don’t dislike Season 15). That’s two very palpable hits: the show hasn’t had as good a start to a season since Tom Baker took over. This is shaping up to be fantastic.

Next episode: The Stones of Blood