It’s fair to say that The Sensorites is something of an unloved story amongst Doctor Who fans (often regarded as nothing more than an excellent cure for insomnia). I think this is a tad unfair (it’s never been a story I’ve struggled with too much). Yes, some of the plotting is a little simplistic, but then the series was still feeling its way during this point, so a little slack needs to be cut.

Probably the most notable part of the serial is that the Sensorites aren’t mindless monsters – they have an ordered society and their decision to imprison Maitland’s ship in an endless orbit is revealed to be an exercise in defence, not attack.

This possibly shouldn’t come as a surprise for anybody re-watching season one in order. We’ve yet to get to the point where non-humanoids are regarded as evil by default. So far only the Voord (underdeveloped as they are) match the template of a monster who desires to dominate others (later to become a familiar Doctor Who trope). Even the Daleks in their first appearance aren’t interested in conquest – survival is the only thing on their minds.

Quite a few six-parters employed a 4-2 or 2-4 format (good examples are The Seeds of Doom and The Talons of Weng Chiang). The Sensorites does something similar – episode one and two take place on Maitland’s spaceship whilst the remainder relocates to the Sense-Sphere. Although here it’s done for more practical reasons, as the studio was too small to house all the sets.

We open with a mystery – the TARDIS materalises inside a spaceship and the Doctor and his friends find two people – a man and a woman – who are both apparently dead. They’re just about to leave when the man stirs and shortly after he explains that they’ve been put into a deep sleep by the Sensorites, who live on the nearby planet.

Lorne Cossette (as Maitland) gives a strange and unconvincing performance, so it’s a blessed relief that he doesn’t travel down to the Sense-Sphere with the others later on. But there is a line of dialogue which suggests he’s been deeply affected by the Sensorites, so that might explain that Cosette isn’t just indulging in a spot of bad acting (although I’m not convinced). Ilona Rodgers (as Carol) has equally earnest dialogue but manages to make a slightly better job of things.

The Doctor’s still in full run-away mode – after a brief chat with Maitland and Carol, he decides there’s nothing he can do to help. So if the Sensorites hadn’t stolen the lock of his TARDIS he’d have been quite happy to nip off and leave them to their fate ….

But once circumstances force him to take action, he does so with gusto – elbowing Maitland aside as he takes control of the ship. Newman gives Hartnell some lovely lines, such as “it all started out as a mild curiosity in a junkyard, and now it’s turned out to be quite a great spirit of adventure.” My favourite comes a little later in the episode. “I learned not to meddle in other people’s affairs years ago. Now, now, now, don’t be absurd. There’s not an ounce of curiosity in me.”

Barbara and Susan meet the third member of the crew, John (Stephen Dartnell). Dartnell, who had played Yartek, leader of the Alien Voord in The Keys of Marinus, gives easily the best performance of the three crew-members. John was the most deeply affected by the Sensorites’ mental attacks and it’s left him in a very fragile state. Maitland believes that he’s potentially dangerous, although the reason for this is never explained. We later learn that the Sensorites have control of John’s mind – had they ordered him to do something violent prior to the Doctor’s arrival? If so, it seems rather out of character for the Sensorites, since it’s stressed that they haven’t actually hurt the Earth people.

The scenes of the zombie-like John stalking Susan and Barbara are effective, although it’s all done very slowly. But when he eventually does run them down it’s clear he poses them no threat – Barbara cradles him as a mother would a child.

The reveal of the monster at the end of episode one would become a familiar Doctor Who staple. We’ve already seen it happen in The Daleks and it happens again here. After an episode of discussing them, things would have fallen rather flat if they hadn’t convinced. So it’s lucky that our first glimpse of a Sensorite is eerie and unsettling.