There’s a definite sense of events spiralling out of control in this episode – for both sides. The Doctor and his friends have essentially taken charge of the resistance, giving the orders, organising the troops and planning a strike at the heart of the warmonger aliens’ power. Meanwhile, the War Chief and Security Chief’s mutual suspicion has prevented them from taking effective action to re-establish control – and in response to worrying reports the big boss has arrived, and intends to oversee matters personally. The back-and-forth between the two sides is beautifully encapsulated in a neat bit of a dialogue:

WAR CHIEF: I suggest we pay particular attention to the 1917 zone.
SECURITY CHIEF: Is that where they are going?

JAMIE: Well, where are we going Doctor?
DOCTOR: Anywhere but the 1917 zone, Jamie.

The baddies get a good chunk of the screen time, with special focus on the War Lord, whose existence has been trailed for a couple of weeks, and who doesn’t disappoint. It’s a great performance from Philip Madoc, peering hawkishly through his bottle-bottom glasses, smiling without any warmth as he issues his chilling diktats, and allowing his subordinates enough rope to hang themselves before he takes charge himself. He only shouts once. The rest of the time, he’s a model of controlled fury, with a sadistic glee as he plays with brainwashed humans as if they were toy soldiers. And it also helps that Edward Brayshaw and James Bree both give every impression that they’re terrified by the War Lord and deeply uncomfortable that they’re under scrutiny.

Edward Brayshaw is, again, particularly interesting as the War Chief. Just like the Master, he seems to admire the Doctor as much as hate him: ‘What an ingenious fellow he is,’ he declares having realised that the Doctor has stolen the master controls for the SIDRATs. He also manages to perfectly deliver one of the most tongue-twisting lines Terrance Dicks ever wrote: ‘We are carrying out a delicately controlled operation. The presence of guards in the time zones could stretch the credulity of the processed humans.’

In short, he’s a worthy opponent for the Doctor, who remains cagey but whose familiarity with all aspects of the War Chief’s technology is obvious. There’s clearly no doubt that the War Chief’s travel machines are ‘just like the TARDIS’ (as Jamie keeps pointing out), but naming them SIDRAT in dialogue for the first time (presumably a rubbish anagram invented by the War Chief to conceal the face that they are TARDISes) is another obvious hint.

This is also a great episode for Zoe, who rides to the the rescue of the Doctor, Jamie and Carstairs at the head of a band of resistance soldiers. And after David Troughton turned up last time, this week it’s Peter Craze, brother of Michael, as a captured French soldier, which means Troughton’s final story feels like a real family affair.

Next episode: The War Games – Episode Eight