‘I think your colony of Earth people is in grave danger of extinction.’ Christopher Hamilton Bidmead returns to Doctor Who with an episode that – perhaps unconsciously, but probably not – evokes Season 18 in its tale of a desperate colony centred around an ancient spaceship and a terrible secret. The leaders of Frontios, like the Deciders of Alzarius, know there is something very wrong, but hide the truth from the wider community. The connections to both Bidmead’s previous stories and Season 18 are reinforced by Paddy Kingsland’s final score for the series – another hauntingly evocative composition.

Bidmead’s idiosyncrasies are on display – the fetishism of information, which is jealously hoarded (even, here, by the Doctor, who declines to share humanity’s spoilers with Tegan). Knowledge has been lost, its re-attainment is a goal. The locals watch the new arrivals with curiosity, just like they did in Castrovalva. The scientist Range talks poetically of ‘the long path back to knowledge’ while the security officer Brazen closes down research. The colony’s leader, Plantagenet, is a “callow youth” pulled between Brazen’s suspicion and Range’s inquiring mind. Rather wonderfully, he speaks like Bidmead taking the mickey out of Saward’s dialogue, all cod-Shakespearean perorations. Fittingly, his office, with its elevated desk, looks like it’s come from a BBC Shakespeare production of Henry VI.

Into the middle of this wanders the Doctor. On the basis of this, I only wish Bidmead had consented to remain for Season 19, and we might have had four years or more of Davison. This version of the fifth Doctor is scatty, insouciant, sarcastic, driven, decisive – all the elements Davison’s brought to the role across the last couple of years are in there. The difference is, Bidmead writes for the Doctor he wishes he’d had during Season 18, whereas, I think, some of Davison’s scripts were written to be “not Tom Baker”. Davison rises to it with a storming performance, once again bettering himself. He gets jokes (‘Not hat people, are you, either of you?’), rushes in to help when he sees injured people, peers at Range over half-moon spectacles, and politely listens to Platagenet speechify before getting back to the practicalities of the situation.

Fair enough, the sub-plot of Tegan and Turlough stealing a battery is spread thin, but even that gives them something more useful to do than anything they’ve had in a while, and it’s an opportunity to explore more of the world Bidmead’s created, realised pretty effectively by David Buckingham. And with some clearly painted peril (these people on the brink of extinction are among the last human beings; the TARDIS has been destroyed) this is right up my street.

Next episode: Frontios – Part Two