The Macra Terror gets more ordinary and less interesting as it goes on. This final episode consists of the Doctor mucking about with some switches, running through a corridor, and unmasking the Macra to the Pilot – whose response is pretty understated given his entire worldview has just been torn down in front of his face.

It doesn’t help that the Macra, while quite fun monsters, make rubbish villains. They’re great when they’re lurking in the shadows of the old mine, menacing Jamie. They’re a lot less effective when they’re impotently trapped behind glass like bottled spiders, speaking with panicky middle class voices like they’ve escaped from an episode of Ever Decreasing Circles. Troughton has nothing to play against – the Pilot has come over to his side, Ola is too flimsily characterised to be useful as a last-act antagonist – so the ending relies on Ben coming to his senses and pressing some buttons as guided by the Doctor (uncharitably, swapping one controller for another).

So far, Troughton has been badly served by his enemies. Perhaps that’s why he’s remembered as the “monster Doctor” as he mostly faces expressionless, identical monster costumes. Hartnell got Tlotoxl, Emperor Nero, Mavic Chen – even the Toymaker and Captain Pike. Troughton’s had Solicitor Grey and Professor Zaroff. He really needs a proper opponent to pit his wits against, rather than monsters to run rings around.

The episode isn’t a completely damp squib – as noted, the Macra are good when they’re allowed to be monsters, and Jamie’s Highland Fling is funny. There’s a brilliant moment when Troughton strides into a confrontation between Ola and the Pilot and tells them both to calm down. But on the whole this is a weak ending to a story that as much as any to date has got worse with each episode.

Next episode: The Faceless Ones