When I’ve come up to one of the all-time classics as I’m watching the series through episode by episode it’s always obvious how the great stories aren’t flukes, but the show in whichever form it’s currently in getting everything it’s currently doing right. Genesis of the Daleks was veteran Terry Nation’s third script in as many years, heavily reworked by the script editor and shot by an experienced director. The Brain of Morbius and The Talons of Weng-Chiang: similar stories. And City of Death is similar again: David Fisher’s fourth script, reworked by Douglas Adams, and directed by Michael Hayes. It is serendipitous that this is also the one chosen for the show’s first overseas filming, but it’s no accident that this works.

Since Graham Williams took over the show’s model work has come on leaps and bounds, and the opening sequence, of a spider-like spacecraft squatting malignantly in a wasteland, is one of the best yet. And the design, which hasn’t always been of the same quality, is up to scratch too: I love how the Professor’s time machine echoes the spider legs of the Jagaroth spaceship, drawing a subtle link between the two even before the cliffhanger makes it explicit. Dudley Simpson’s score is spot on, with a slight hint of the Pink Panther theme as befits a crime caper. The shift from Hinchcliffe horror hits a new level of sophistication. Scene transitions are smart (conversations about time between the Doctor and Romana, the Count and the Professor intertwine). You could stick this on stage and it’d work as a light comedy.

The actors approach it in the right spirit: there’s no embarrassing Davyd Harries pratfalling here. Julian Glover and Catherine Schell play the Count and Countess as partners in crime rather than lovers, implying acres of backstory with the arch of an eyebrow or a tight little smile: ‘What else have I been doing all these years’; ‘Overcome by your charms?’. I like the slight hint that Hermann and the Countess might have something going on – the way he looks at her when they’re alone suggests that.

I mean you could point out the little flaws (like Scaroth’s ill-fitting gloves in the prologue) and wonder whether kids in the audience would be as indulgent as I am of the Parisian interludes, but when the material is this good ‘let them gape, what do I care?’

Next episode: City of Death – Part Two