Ian and Susan rescue the Doctor from the mysterious creature in the aqueduct. The Doctor implies that there’s something strange about the monster (otherwise how could it have ripped his coat to shreds but not touched his skin?). You have to assume that the monster, like the poisoned water, has been arranged by the (as yet) unseen survivors from the human spaceship which landed ten years ago. Quite how they were able to create the illusion of this monster is a mystery though (and if they are responsible, don’t the Sensorites think it’s strange that mysterious creatures suddenly appeared in the aqueduct some years ago? Where had they been before that?)

The Sensorites continue to maintain that they have a perfect society. “Our society is based upon trust. Treason or secret plotting is impossible.” But the continuing plots of the City Administrator (and the fact that he is able to recruit willing helpers) sharply contradicts this. It’s possible to argue that it’s only the arrival of the humans which has caused the Administrator to go off the rails, but this doesn’t quite hold up to scrutiny. Because he reacts so strongly (and with very little provocation) it does seem probable that he would have snapped soon anyway. And if the Sensorite nation is so peaceful and well-ordered, why do they need a Warrior class?

I like the way that that Sensorites are able to run the Doctor up a lovely cloak to replace his ruined coat. It’s hard to imagine that Sensorites themselves wearing cloaks, but maybe they do – otherwise surely they’d get a little chilly in the winter time?!

There’s a few line fluffs in this episode, but Hartnell’s not to blame for once. This is my favourite, courtesy of one of the Sensorites. “I heard them over, over, talking”.

Carol gets a decent share of the action in this episode. She shares some key scenes with the Sensorites, is overjoyed when John is returned to normality (which is a well-acted scene by Stephen Dartnell) and finds herself kidnapped at the end of the episode.

It’s unusual for a non-regular to be the focus of the cliff-hanger, especially as Susan could easily have been substituted for Carol. Maybe it was felt that since Susan was kidnapped at the end of episode five of The Keys of Marinus it would have felt too much like deja-vu had it happened again so quickly.