Introduced as a direct substitute for Susan, Vicki has – until now – rarely been a character who has initiated events. In her previous stories she’s spent most of her time with the Doctor, which has fostered the impression that she’s a young and inexperienced girl who needs guiding.

But whilst she may be young there’s also been various hints along the way that the schooling she received in the future was well in advance of anything that Ian and Barbara would have taught their pupils. In this way she’s very much a proto Zoe – immature but with a strong intellect.

This is the episode where she steps out of the Doctor’s shadow, as we see her organise the Xerons into a revolutionary force. Like the rest of the story this is a little hard to swallow (Vicki is an unlikely revolutionary) but by all accounts Glyn Jones’ original draft scripts were much more light-hearted (script editor Dennis Spooner removed most of the overt comic moments) which might explain why the end product feels a little disjointed.

The Xerons explain to Vicki that the Moroks devastated their planet. “They destroyed everything, even our people. Only the children were spared, to work.” This is slightly odd – quite how efficient children would have been as a working force is debatable, surely it would have been better to keep the adults alive to work as slaves? But it’s a heart-wrending story and provides Vicki with a good incentive to help them, although her desire to ensure that she and the others don’t end up as exhibits in the museum is an even stronger one.

Vicki’s skill with computers (another trait she shares with Zoe) is sort of demonstrated when we see how she bypasses the electronic brain which guards the Xeron’s armoury. The computer is designed to only open the door if the answers received to a set series of questions are both truthful and correct.

Vicki is able to bypass this by speaking the truth when she tells it that she’s Vicki and she wants the guns for revolution.  Best just to ignore this massive cop out I think. As you might expect, what we see is a typical 1960’s vision of a computer – a very bulky, solid-state affair, with whirring tapes spools housed in big cabinets.

Whilst Vicki’s running around having most of the fun, what of the others? The Doctor’s been sitting this one out and won’t return until the next episode, Ian has spent his time getting into fights and waving a gun around whilst Barbara hasn’t had a great deal to do (mainly she’s been attempting not to choke from the poison gas pumped in the museum by Lobos).

Peter Diamond, who teamed up with William Russell in The Romans, makes another appearance here – although this time, as a Morok soldier, he and Ian are on opposite sides. Once again working as both an actor and a fight arranger, Diamond was able to choreograph some reasonably decent fight scenes which allow Ian to throw various Moroks about in a nifty fashion.

Ian reaches Lobos’ office and he orders the Morok commander at gunpoint to release the Doctor. Lobos tells Ian that it’ll achieve nothing if he kills him. Ian responds “possibly, but it might be enjoyable.” This comment is so uncharacteristic that you have to assume he’s bluffing, or maybe all the fisticuffs and gunplay have made him imagine he’s James Bond?!

The episode ends with Ian horrified to see a frozen Doctor. Well sort of. Hartnell’s still on holiday, so Ian has to react to nothing and the audience is required to fill in the blanks.