‘We’ve started a revolution, Leela!’ This feels like an Andrew Cartmel story 10 years early, with the Doctor bringing down a planetary dictatorship overnight, and a final confrontation with the deposed tyrant weeping on his throne as his power collapses around him. Even some of the lines sounds like they come from a McCoy story: ‘I won’t kill you, just close you down’. For all that this was inspired by Robert Holmes’ annoyance at HMRC, there’s a fairly radical message. ‘Don’t you think commercial imperialism is as bad as military conquest?’ snaps the Doctor, off-handedly condemning the British Empire and the USA. ‘We have tried war, but the use of economic power is far more effective,’ replies the Collector (who, it turns out, is actually a fungus – something that grows fat off the back of other life forms). And once that economic power is broken, the Collector, and the Company, go down the toilet – literally.

But Holmes is far too cynical to allow that the rebellion is entirely a good thing. ‘Praise the Company’ is quickly replaced with ‘Long live the revolution’, and (however much he’s redeemed himself) Mandrel’s thugs are now in charge. Veet incites a mob to hurl Gatherer Hade off the Megropolis roof, ironically condemning him to the same death that nearly awaited Cordo in the first episode. And Marn, smelling the way the wind is blowing, abandons her colleagues in an instant, with a smile. This isn’t bloodless, and, as in The Face of Evil, the Doctor is more interested in tearing down a tyranny than preventing another from rising.

Ambiguities aside, I love how this has all escalated from the Doctor and Leela saving one man’s life, and how Cordo develops from a broken nobody into the gun-toting rebel firebrand of this episode, just as Mandrel moves from vicious thug to almost pathetically hopeful about a future on Earth. I don’t give him five minutes once Veet realises he’s gone soft. The characterisation is strong. Leela gets to throw a knife. K9 helps save the day (after everyone has to call after him as he’s wandered off like a proper dog), and the Doctor gets several moments of comedy (the safecracking, and admitting he’s ‘Quite mad, mad as a hatter’) and an equal amount of fury. Even the final TARDIS scene is funny.

This is one of my favourite kinds of Doctor Who story: like The Happiness Patrol and Gridlock, it posits a skewed version of our own society, and proceeds to unleash the Doctor on it. It’s not perfect, but I think it nails the new, big, comic book approach far more successfully than The Invisible Enemy, and is one of Robert Holmes’ most joyfully unbound scripts. Easily the highlight of the season so far, and, at least for me, one of the series’ underrated triumphs.

Next episode: Underworld