“We no longer execute our hardened criminals and killers,” witters Professor Kettering (Simon Lack) in the first episode of The Mind of Evil. “Modern society has progressed far beyond that primitive form of retribution.” Yup, capital punishment’s right out, but performing brain surgery in order to leave them passive dullards is absolutely fine.

The Mind of Evil‘s central premise is a little iffy, with more than a hint of social engineering about it. After the mysterious Keller process is undertaken on hard case Barnham (Neil McCarthy), Professor Kettering (of Which University) promises, “he will take his place as a useful, if lowly, member of society.” His place. Useful. Lowly. It’s all a bit Orwellian. It’s just as well the Doctor (the Pert, with authoritarian front) takes a dislike to it from the start.

But it would be nice if he directly objected to it. He’s worried about the Keller machine, sure, but he’s worried about the threat it might cause to the outside world, seemingly about what happens to the “evil impulses” sucked out of convicts and stored in a natty little tank. He really should at some point say that apart from any external risk it represents,what is in effect lobotomising people is a pretty sucky thing to do.

It’s just one of many things going on in this story. Russell T Davies has talked about Doctor Who‘s ability to gobble up plot like no one’s business and you can see it on display here. The Master (Roger Delgado), this season’s house villain, has no less than three wicked schemes: sabotage a peace conference, steal a nuclear missile and unleash an alien mind parasite (the creature lurking inside the Keller machine) on the world. And even so, there’s still not quite enough going on to sustain six episodes. Like most six parters, it should have been four. Events keep repeating: riots, cliffhangers, locking the Doctor and Jo up.

Part of the problem is the Keller machine itself. Being essentially a brain in a box, it might be dangerous but it’s not very mobile. So for it to pose any threat, our heroes have to keep finding excuses to go into the room it’s locked up in. It’s not until Episode Four that our monster of the week makes up for its lack of legs, by magically learning how to teleport itself to exotic locations, like the next room along. Director Timothy Combe does what he can to make this mini juke box look menacing with some giddying swoops of his camera and some jaunty angles. Composer Dudley Simpson helps with some portentous music, but it’s a tough job to make it look menacing.

It has also changed its modus operandi by the time it starts beaming itself short distances around the studio. In the early episodes, it kills folk by amplifying their greatest fear. Kettering for instance, is terrified of water so he drowns in a dry room, and, again as if by magic, his lungs fill with water. “We believe what our minds tell us too,” flubs the Doctor, to cover over this implausibility.

The Doctor turns out to be terrified of black and white cut outs of old monsters flying at his head. The Master is scared of staring up a giant Pert’s nostrils. But by the time the Keller machine gets round to killing a few extras, it’s forgotten about dredging up the dreads, and just zaps people in a shower of static. Which leaves us to imagine what the crippling phobias of the expendable prisoners and guards are. I like to think they are of the oddly mundane variety. Buttons.The colour yellow. The lack of a fulfilling acting career.

The prison setting makes The Mind of Evil feel quite different to other Whos. I’m reluctant to use the overused term ‘gritty’ (although it is an adjective often applied to these earliest of Pertwee stories) because I think Doctor Who is always too fantastic for that. But still, we’re in a prison, which is not as cosy a setting as Doctor Who normally inhabits.

But this attempt at realism is countered by an air of unreality. This looks like a very BBC prison to me. The prisoners are all neatly dressed, all the way to their neckties. The walls aren’t brick, but vac formed plastic sheets. We never actually see a prisoner in a cell. (Oh, and yes, that whole alien mind parasite thing’s a definite challenge to realism.)

This strange mix of reality and unreality runs through The Mind of Evil. For instance, real world tensions between the US and China are mirrored here, though the very notion of them attending a ‘peace conference’ is fanciful. Not to mention that the Americans have sent a chief negotiator to this conference who has a profound fear of the Chinese, which results in the Keller machine prescribing death by oriental dragon. How did that sneak through Senator Alcott’s (Tommy Duggan) personality profiling?

Or what about how the Doctor drops the real world name of Mao Zedong (not something he’d rush to do these days I suspect) and enters into a conversation in Hokkien, to give the impression of someone familiar with Chinese culture. But earlier in the story, in my favourite bit in the whole story, he deduces that the assistant who accompanied the Master to install the Keller Machine at Stangmoor, and peace conference delegation member Captain Chin Lee (Pik-Sen Lim), must be the same person because they’re both described as “attractive Chinese girls”. I mean, of course! How many of them could there be?!

No actually, that’s not my favourite bit. My favourite bit is when the story acknowledges the very fine line it’s walking between realism and fiction. It comes when the Brigadier (Nicholas Courtney) and Major Cosworth (Patrick Godfrey) are plotting a break-in to Stangmoor. Problem is Stangmoor’s an old fortress so getting in is going to be quite a task. But then Cosworth seems to speak with the writer’s own voice as he works out a solution to this plotting problem:

COSWORTH: I suppose there couldn’t possibly be a secret underground passage or something?

Of course there could! And what’s more…

BRIGADIER: Yes, you’re right. It hasn’t been blocked off either. It probably leads to the old dungeons.  

I’m sure it does! Problem solved.

COSWORTH: It’s rather like making a film, isn’t it Sir?

Yes, Cosworth, that’s certainly what it feels like watching it.

LINK TO A Good Man Goes to War: prisons in both.

NEXT TIME… The monkey house is nearly full, but there’s room enough for you. Cue the Ghost Light.