‘Everything’s beginning to fall into place.’ Oddly prescient, this, given Thatcher’s own astonishingly rapid betrayal and defenestration by her own people following the Poll Tax riots. As the Killjoys march on the capital and the ‘drones’ in the factories she’s built turn against her, Helen A is brought down by dissent in the Happiness Patrol ranks before she’s savaged by her own dead sheep of a husband. ‘A little local difficulty’ quickly turns terminal. All political lives end in failure.

Again, the intent of this is better than the execution, which is as choppy as the rest of the story. The fall of the Terra Alphan regime should be quick, but the crucial moment feels too blink-and-you’ll-miss-it: the Doctor doing stand up while the protesting drones throw off their weeds and the factions of Happiness Patrol commandants turning on each other. This scene is a mess as staged, with little sense of what’s really going on and too few walk-on actors, and I think this undermines the rest of the episode.

Which is a shame, because the just desserts in this are as good as anything the series has done: the Kandy Man becomes the victim of his own cruel execution method, the Happiness Patrol become the new drones, lift muzak is replaced by the blues, and Helen A, finally, learns that happiness isn’t cosmetic and is only meaningful if the possibility of sadness exists. The last line, ‘happiness will prevail’, is perfect.

The story as a whole is flawed, but brilliant, agitprop for kids, with some real anger like the scene where the Doctor unrolls the scroll of Helen A’s victims. You could argue Doctor Who shouldn’t be comparing a popularly-elected government to a fascist regime, but the presentation here as over-the-top satire fits in to a longer tradition in British comedy: it’s Spitting Image not a serious suggestion that the Conservative Party sent out death squads to disappear Thatcher’s enemies. I really like it. If the next story’s any good we could be on track for the best series of the 1980s.

Next episode: Silver Nemesis