About half the episode revolves around the Doctor and Jamie being tested for intelligence and physical strength aboard the Dominator ship, which basically means Troughton and Hines get to muck about together playing dumb and having fun, and being immensely charming – as a result, this is probably the most straightforwardly entertaining episode there’s been since The Web of Fear.

The flipside is that the other half of the episode doesn’t amount to anything very much at all. Cully and Zoe go to the capital, meet some more old men like Director Senex who don’t believe their story, and then go back to the island of death. It’s quite disappointing that in her first proper story Wendy Padbury’s being given next to nothing to do. Meanwhile, Educator Balan pooh-poohs his students’ credulity and refuses to believe that Dulkis has been invaded – but consents to go and look for the Doctor and Jamie at which point the Dulcians are all captured and subjected to another set of tests.

The theme of the story seems to be rebellious and questioning youth pitted against the settled, complacent ideas of their elders. The Dulcian seniors are a fairly condescending lot, more interested in decadent debates about holiday zones and accepting facts without question, while refusing to countenance anything that falls outside the scope of their understanding. Likewise Probationer Toba bridles at Navigator Rago’s weary insistence on conserving power and doing things by the book. Young people like Cully and (at a push) Toba want to be recognised for their own achievements, rather than living in the shadow of their elders and betters. This is very much in the spirit of 1968.

Sadly, for such a topical subject, the authors seem to be ambivalent about taking sides. The young Dulcians are as bland as their elders, and Toba’s repeated desire to blow things up is clearly meant to be a joke, but it’s not very amusing to start with, and none of this is executed with enough awareness of the comic potential of the script. Instead, Morris Barry directs it all with a leaden pace and the apparent belief that it’s meant to be a B-movie horror like The Tomb of the Cybermen rather than a satire of the 1960s.

This episode also gives us our first proper look at the Quarks, which are quite a fun design (although in no way ‘new Daleks’), a collection of shapes thrown together like geometric abstract sculptures. The way they toddle about, flap their arms and spin round on the spot to record data is a bit stupid though.

Next episode: The Dominators – Episode 3