This opens almost exactly like The Time Warrior with yokels watching a falling star land somewhere nearby. Given this introduces the Sontarans’ arch-enemy, the Rutans, it has to be an in joke between Terrance Dicks and Robert Holmes, and it remains one of the most beautifully subtle kisses to the past in the series’ history. The difference is that when Holmes wrote The Time Warrior back in 1973, the concept of the Doctor Who historical had been more or less dead for half a decade, but since Hinchcliffe took over it’s become, if not the norm, then very much one of the main types of story. It almost feels as if this picks up where The Talons of Weng-Chiang left off, with Leela in period costume arriving in turn-of-the-20th-Century fog to learn more about her human ancestors.

Those ancestors, so far, are a trio of lighthouse keepers sketched with Terrance Dicks’ usual pithiness. Reuben is the old hand, conservative and suspicious of the modern innovations like electricity championed by the other experienced keeper, Ben. Vince, the eager trainee, is treated with indulgence, like the son in this odd little family. It’s the first historical base under siege since 1967’s The Abominable Snowmen (novelised by Dicks in 1974), and exploits a strand of isolated, And Then There Were None type horror that Hinchliffe only really explored in parts of The Seeds of Doom. The Doctor and Leela’s arrival minutes after the Rutan’s, just in time to discover the electrocuted body of Ben, is very like the second Doctor’s arrival at Det-Sen just after Travers’ companion has been killed by something alien in the darkness.

For all the production challenges, this looks great. There are some wonderful moments of Leela roaming the misty shore of Fang Rock, and of the Doctor silhouetted in the fog against the light from the engine room. The constraints of the Pebble Mill studio facilities probably work in the story’s favour, as it looks appropriately claustrophobic. Only the climactic model boat crash is disappointing. I also like that the Doctor seems to be developing a friendly relationship with Leela, rather than the teacher/pupil dynamic of Season 14. They get some great banter in this (‘teshnician’). And while the fourth Doctor is at his most impishly Troughtonish (trying on a new hat, looking broody, then giving Reuben a cheeky wink), Leela is back to her Talons tricks, stripping off in front of a helpless Vince to change into dry clothes. This is great.

Next episode: Horror of Fang Rock – Part Two