The stakes of the story are clearly articulated in the first scene: ‘Who will live to serve the machines, and who shall be eliminated?’ Everything that follows flows from this mission statement, as individuals with no further use are ruthlessly dispatched – not just the hapless tramp who wanders into WOTAN’s warehouse, or the worker who becomes a test subject for the first of the War Machines, but even Dodo Chaplet.

This is brilliantly directed, with loads more film work than is normal. The scenes of the War Machines being manufactured look great – little trucks, crates piled high, and the tramp who’s just been propositioned by Ben running for his life as the zombified workers close in around him, and dispatch him offscreen before a brutal cut to his photo on the front page of the next day’s newspaper under the headline ‘Dead Man Found in Garden’. (Although – how this managed to make the next day’s papers is a mystery, given the first editions must have been printed before he was killed).

Without being overly showy, Ferguson drops in quite a few stylistic touches. WOTAN’s initial briefing, which could have been just three men talking to each other, is instead imagined as a series of theatrical talking heads. He also throws in a few Dutch tilt establishing shots of the Post Office Tower to emphasise its off-kilter nature.

Most impressive of all is the sleight of hand pulled off by Ferguson and Ian Stuart Black – who craft an episode that begins with Dodo in peril and ends with Ben and Polly in danger. As we focus on the two of them, we miss the fact that the de-programmed Dodo has been sent to the country, never to be seen again. At the end of the first episode, Dodo seemed to be the focus of the story. By the end of this one, she’s become irrelevant. It gets a lot of criticism now, but it seems to me a more elegantly executed exit than Vicki or Steven got, and a much more graceful transition to Ben and Polly than the hasty introductions of Katarina or Dodo herself.

It’s a shame Jackie Lane fell victim to Innes Lloyd’s regime change, as in context Dodo is a really significant companion – the first contemporary, “feisty” young woman, and therefore the archetype for the vast majority of the Doctor’s companions since. She deserves to be remembered for more than her array of accents. But with only a four-month tenure (compared to a year or so for her predecessors), as the only Hartnell companion never to meet the Daleks (even though the Doctor keeps teasing their arrival – in both The Savages and this), and without appearing in any “Whovian canon” stories it’s unlikely she’ll ever get much attention. I do hope Jackie Lane knew she got the biggest cheer at The Day of the Doctor after-party though.

That said, Ben and Polly land brilliantly. Quite apart from Anneke Wills’ screen presence, Polly is as convincingly “realistic” as Barbara, in a way that the futuristic space girls Susan and Vicki were never meant to be, and Dodo didn’t quite manage. She’s got a job, a boss, friends, and a life outside of the TARDIS. Though less characterised, Michael Craze is charming as Ben: prickly (‘I’m no deb’s delight’) but compassionate (checking whether a tramp is OK).

The Doctor pootles through it all as he usually does – finding out who’s in charge and inveigling his way in just like he did at the court of King Richard or Emperor Nero. This time, it happens to be the town house of a 1960s British knight. What’s more perplexing – although it is the third time it’s happened in the last three months (see also the Toymaker and Jano) – is that the baddie knows who he is, and has been waiting for him. And WOTAN rightly knows his name is Doctor Who…

Next episode: The War Machines – Episode 3