The trouble with Revenge of the Cybermen is it’s not entirely clear what’s at stake or why we should care. The base under siege promised in Part One never materialised – by the end of Part Three Nerva has been abandoned to the Cybermen. The CyberLeader talks of building an invincible new CyberArmy (presumably armed with CyberBombs) but the Doctor kicks the legs out from under this idea, mocking it and the Cybermen so effectively that it’s hard for us to see them as a credible threat (possibly Tom Baker letting his boredom with the script come through too clearly). Then there are the two equally dull factions of Vogans, whose squabbles are so presented in such an abstract way that it’s impossible to choose between them. Their dialogue is atrocious. Even Kevin Stoney can’t save lines like line, ‘Has Vorus in the madness of his vanity brought down the vengeance of the Cybermen upon us again?’

Compared to the pervasive sense of dread in Genesis of the Daleks and the creeping horror of The Ark in Space, this is very thin indeed. Some of the individual moments of peril – the Doctor being turned into a walking bomb, for instance – are quite good, but they’re hung on a terribly flimsy frame. There are some influential ideas introduced here. Kellman is a prototype Lytton, a mercenary in it for the money who turns out to be slightly more complex than first appears. The CyberLeader has emotions and says ‘Excellent!’. The Cyber aversion to gold is stupid (why wouldn’t they just upgrade themselves? Surely it would be easier than trying to remove all of the gold from the entire galaxy? Why don’t the Vogans just use a glitter gun against them?). It’s not even like it represents some sort of Star Trek theme of capitalist greed for gold versus drone-like Cyberman collectivism.

The good bits continue to be Michael E Briant’s reliably muscular direction – the film work looks great; the Cybermen are almost luminous as they stride through Wookey Hole (although the Vogan soldiers in their flowing white wigs and crocheted dresses look exactly like the killer in Pete Walker’s 1978 Britsploitation movie The Comeback). Even the mix of location and studio caves works better than it normally would. The music, including the first (uncredited) contribution from Peter Howell, is superb: there’s a Halloween-type motif as the Cybermen stalk through Nerva, and a pulsing heartbeat at the climactic avalanche.

Next episode: Revenge of the Cybermen – Part Four