The planet in the title is Desperus, and I think ‘Desperation’ might have been a better title for this episode. Not because it lacks incident, more because right from the off there’s a real sense of mounting hysteria right across the board.

On the stolen Spar, Vyon halts the launch just long enough for the fleeing Doctor to get on board with the stolen Taranium. ‘Get us off! Take off man!’ he bellows, desperately. They manage to get away from Kembel and into space, but the pursuing Daleks are not far behind.

On their end, the Daleks seem equally desperate. While the troops have mobilised a pursuit ship and are ready for the ‘space extinction’ of the fugitives, a panicked Black Dalek shrieks that the intruders must be caught alive: nothing can be allowed to jeopardise the precious Taranium Core (which, wonderfully, we get a glimpse of, glowing with radioactive energy and viewable only with special sunglasses which leave your hair mussed up).

Elsewhere, the Planetarians are in a tizzy. The Daleks blame Zephon for the fiasco; Zephon blames Chen; Chen brushes it all off. A scapegoat is required and so frond-face gets his desserts. Of course, the real idiots are the Daleks for letting the Doctor and Vyon evade them, but they’re admitting nothing.

The Dalek pursuit ship forces the Spar down onto Desperus – home of the desperate inmates of the Solar System’s prison planet (we assume this is a planet belonging to the Solar System, rather than in it). The very hirsute castaways Bors, Garge and Kirksen fear the imminent arrival of the Spar as they expect it brings fresh inmates who’ll usurp their positions. But Bors has a knife, and he’s planning to use it to escape the filthy planet.

Ever since someone pointed out this adventure is like a prototype for Blake’s 7 I can’t help hearing it lines like ‘That’s why we’re stranded on this pimple of a planet’ or seeing it in the desperate attack on the Spar by the prisoners (we don’t see it in the infamous Screamers because they’re barely visible, shadows flitting around). But equally, this is completely Doctor Who: I adore the Doctor’s impassioned defence in the face of Steven’s sarcasm, ‘Don’t you start to criticise my TARDIS. And as for space travel, you’re still wet behind the ears.’ This leads to my favourite moment in the recovered episodes: Vyon and Steven sharing a look and a moment: ‘What’s the matter with grandpa?’

While the episode largely focuses on an extended diversion, it serves to show the danger the TARDIS crew and Vyon are in, adds some flavour to the story by showing the dissension in the alliance ranks, and a prison colony of the year 4000, suggesting a lot of the Solar System’s power is built on controlling its population. And Katarina’s chilling scream at the cliffhanger is truly terrifying because it’s the first time we’ve really seen her show any emotion. Now we have most of her screen time back, it’s fascinating to watch Adrienne Hill’s performance: baffled incomprehension mixed with a kind of placid acceptance of her fate. Her complete faith in the Doctor means that she even seems completely unbothered at the idea of being set upon by three men.

The recovery of the first quarter of The Daleks’ Master Plan reinforces its status as a classic, full of neat directorial touches, committed performances and a sense of jeopardy and scale –in the “conquest of the universe” plot, the world building and the urgency of Vyon’s mission. Terry Nation thought he could make a series out of this. And in the end, he did.

Next episode: The Traitors