It sometimes feels as if Carole Ann Ford has spent the last fifty years complaining how underdeveloped Susan was. According to Ford, Susan was to be an active, Avengers-type girl with psychic powers, so she was later perturbed to receive scripts where she was called upon to play a character who appeared to be little more than a frightened fifteen year old girl.

Quite how much truth there is in the concept of a super-Susan is hard to establish. I’m not aware of any draft scripts that present the character in this way (and Sydney Newman, who more than anyone can be called Doctor Who‘s creator, was always clear that Susan was to be the audience identification figure – a normal teenage girl).

When the first story was being written, there was some talk about making her an alien princess, but it does seem that very quickly it was decided to keep her pretty much as an ordinary girl (even though it’s established that’s not the case). It was a constant source of frustration for Ford and led to her desire to leave the series at the earliest opportunity – although she was possibly unaware that the production team were equally keen to dispense with her services.

One remnant of super-Susan is touched upon in this episode – a skill with telepathy. Her ability to connect with the Sensorites causes her to act as their intermediary – which concerns the Doctor. It gives Ford a little more than normal to work with, which is welcome, and it allows us another brief look at the unearthly child from the opening episode.

Ian spends part of the episode being stalked, rather slowly, around the ship by the Sensorites. Frightening though they appear, the Sensorites aren’t aggressive – although they do insist that everybody has to come down to the Sense-Sphere to live with them, which doesn’t sound like the best proposition ever. The Doctor, as might be expected, isn’t happy. “I don’t make threats. But I do keep promises. And I promise you I shall cause you more trouble than you bargained for if you don’t return my property!”

Another remnant of the early aim of the series to educate as well as entertain is touched upon when the Doctor discusses how they might gain the upper hand with the Sensorites.

DOCTOR: It’s a fallacy, of course, that cats can see in the dark. They can’t. But they can see better than we humans, because the iris of their eyes dilates at night. Yes.
IAN: What are you driving at, Doctor?
DOCTOR: Oh, it’s all perfectly simple, Chesterton. You see, the Sensorites eyes are the exact opposite to that of a cat. The Sensorites eyes were completely dilated, that is, enormous, in light.
IAN: The conclusion being that they would contract in darkness.
DOCTOR: Exactly. And that is our best weapon. The Sensorites will be frightened of the dark.

There’s not a great deal going on this episode, apart from giving us our first proper look at the Sensorites. But it ends with a jolt – as Susan prepares to journey down to the Sense-Sphere alone (even if, as so often, the cliff-hanger is negated in the opening moments of the next episode).