Malcolm Hulke’s take on the Master is absolutely fascinating. Earlier in the season he’s been both a Bond villain and a dark version of the Doctor, but Hulke gives him a motivation of his own. With the Doomsday Weapon in his grasp, the Master offers the Doctor a half share in the Universe, and he really means it. ‘You could end war, suffering, disease. We could save the Universe… Bring good and peace to every world in the galaxy.’ While he’s clearly a Satanic character – his mantra seems to be better to rule in hell than serve in heaven, and he continually tries to tempt the Doctor – he isn’t just a force of random evil. He’s the classic Sauron/Palpatine/Daenerys type, desiring order, but believing only he can deliver it. Steven Moffat picks up on this characterisation when writing Missy, another incarnation who offers the Doctor absolute power.

Of course, the Doctor rejects it: ‘What is the point? I want to see the Universe, not rule it.’ Hulke, as always, is seeking to write some sort of ethical conflict. The Doctor’s random, on-a-whim do-goodery is as incomprehensible to the Master as his desire for control is to the Doctor. Why save a single life on an obscure planet when you can reorganise the galaxy? The self-sacrifice shown by both the Guardian of the “Primitive” city and Ashe, the leader of the colony is alien to the Master, who doesn’t think in terms of small mercies. This story posits that no-one should have the power of life and death over others, and makes every character who has that power – including Dent – corrupt and self-serving.

While the confrontation between the Doctor and the Master is scintillating. The rest of the episode is almost as strong. Caldwell, whose discomfort with Dent and Morgan’s villainy has been increasing, finally rejects the wealth and power IMC offers to join forces first with Jo, and then to throw in his lot with the colonists. There are some good action pieces, including a brutal fist fight in a mud pit between Winton and Security Guard Rogers (I like that even minor characters are given names), and a final shoot out between colonists and IMC.

The Discontinuity Guide‘s verdict on Colony in Space – ‘Rather like watching socially-aware paint dry’ – is overly harsh. The middle episodes are slow moving, but Hulke’s character work is a strength, as is his commitment to providing some sort of moral dimension and purpose to the whatever he’s writing. This is quite a lot more interesting than the humans vs monsters runarounds of the previous era, and adds some gravitas to Season Eight. And its characterisation of the Doctor and Master’s relationship is definitive. Fair enough, it might have been nice if the third Doctor’s first trip to another world hadn’t been quite so muddy, but after the fizziness of The Claws of Axos, this is something quite a lot more substantial.

Next episode: The Dæmons