Genesis Of The Daleks I think part of the reason for this story's popularity is that it takes the nature of what the Daleks represent (essentially, fascism, or at least the conventional shorthand for that - to wit, aggressive nationalism, or Darwinism taken to militaristic extremes and interpreted in strict terms of ethnic and physical purity) and plays it up to its ultimate. In the middle class BBC drama terms of the era, it's about as grim and pitiless as you could get.

This is demonstrated almost all through the story. The reason why Davros and Nyder appear to have the upper hand until very near the end is because they are prepared to be more ruthless than any of the opposition they encounter, opposition which itself persistently underrates their capacity for murderous double crossing to remove any threat to their ambitions. The Kaled politicians' well-meant attempt to increase the accountability of Davros's experiments is rewarded with the complete destruction of their city, in similar fashion to the way the Thals are soon disabused as to Davros's goodwill towards them, when he dispatches a squad of Daleks to continue the cycle.

There's even an exchange between Davros and Nyder early on which seems to see the latter moving closer toward the former's methodology and motives before fully accepting them (Nyder: "The whole of the Kaled people? You would go that far?" Davros: "Did you ever doubt it? Nyder: (Short pause) "...No."). The significance of that pause is that it kills off any qualms Nyder might have had previously. From then on, he and Davros are of one mind. Nyder has bought totally into the leader worship mentality. For him, whatever is right equates solely to whatever Davros wants or intends.

Davros's solution to any potential threat is to have it eliminated after tricking it into a false sense of security, a technique employed by many of the cruellest dictators. He uses exactly the same tactic on Gharman and his followers when they attempt their revolution. That is Gharman's ultimate mistake - he assumes he is dealing with a reasonable man.

This dichotomy develops from the instant Davros orders Gharman to carry out the necessary chromosomal changes that will result in a total lack of conscience in the Daleks. He questions and argues the point, and from then on the conflict between his own humanitarian values and Davros's ruthless conquest-based ideology (anticipated earlier by Ronson in his gloomy explanations to the Doctor and Harry) comes into a sharper and sharper focus. But both the aims and methods are different. Davros and Nyder have no qualms about using trickery and deception to trap their enemies - Nyder's pretence that he shares Gharman's disquiet, so as to lure him into giving away valuable information, and as a means of confining him to a cell, as well as Davros's false promise that he "will abide by the decision of the majority". Gharman is keen for " a bloodless revolution", protesting "there's been enough killing and destruction", and yet it is clearly implied at the end that only a similar level of ruthlessness to Davros's would have been enough to stop him.

There is a very rare (for Dr Who) attempt to expound on the political philosophy of the main villain, after Gharman becomes the first character in the story to use the word "democratic". Davros pays lip service to this, using it to set his trap ("It was you who introduced the word 'democracy', was it not?"), while privately scorning it ("They talk of democracy, freedom, fairness. Those are the creeds of cowards. The ones who would listen to a 1000 viewpoints and try to satisfy them all. Achievement comes through absolute power, and power through strength. They have LOST!"). It is the typical exaltation of constant war as an absolute good in itself, a source of strength for a nation, along with a fixation with national/racial supremacy, as expressed by the European fascist regimes of the 1930s. Part of the story's moral, a very bleak one, is that it is not always possible to counter a threat on this scale with peaceful and scrupulously fair-minded methods. This is also reflected in the Doctor's anguish in the scene where he tries to destroy the incubation room by touching two wires together, with Sarah urging him on by pressing on him the scale of what he is dealing with.

Davros is a product of his world and seems to have come to dominate the Kaleds by fear and intimidation as much as anything else. Ravon instantly backs down at the thought of having to confront him, and I don't think it's too fanciful to say the Kaled leaders seem nervous of him too. It says a lot for Michael Wisher's powerful performance in the role that he seems to radiate a commanding and forbidding charisma in every scene, effortlessly dominating proceedings. He does descend into the occasional rant, although it never seems contrived and stuck in, always a case of rising anger and determination at some development or other. Mostly however, he plays it with a silky and arresting delivery, with a far greater subtlety, intelligence and believability than any later version (much better mask too).

The story contains a great many pointers to the brutality of wars and dictatorships. Whether it be the the casual callousness of both Kaled and Thal guards, thumping prisoners, almost killing Sarah when she is too slow to stand up, dangling her over the edge of the rocket for kicks or exposing prisoners to radiation for when loading the rocket (presumably not enough to do permanent damage, hence Sarah later suffering no ill-effects). There is the case of the Doctor, Sarah and Harry having to grapple with corpses to get gas masks at one stage, and Ravon giving the official face of the regime to prisoners by producing vicious triumphalist rants of imminent victory that are disturbingly similar to the Dalek's threatening speech at the very end of the story (incidentally, the way in which it appears to be addressing the television audience in close up is a clever touch too). Davros's attempts to coerce the Doctor to talk by torturing Sarah and Harry also recall totalitarian interrogation techniques (forcing you to betray your friends and hence break your spirit - that's partly what Room 101 in 1984 is about).

There are also visual pointers, such as the black uniforms, the insignia Nyder wears, the churned up wastelands for battlefields and the indiscriminate massacres. The opening scene features an army unit being gunned down, and this effectively foreshadows the killing that dominates the story - both the Kaled and Thal cities' destruction, and the Bunker staff being mown down by Daleks at the end. I think there is a very strong case for saying that Blake's 7 - which was first thought up by Nation in 1975, about this time - grew out of Genesis, with its black-clad guards, fascism on a galactic scale and endless massacres (seen in both The Way Back and Blake).

The Mutos are also a pointer to the theme of racial and genetic supremacy. Seen as "imperfections", a threat to the intended purity of the Kaled race, they appear to be a hated and rejected underclass, and yet still able to produce good-hearted people like Sevrin (very much following on from Wester and Bellal, and anticipating Tyssan, in being a seemingly sinister stranger who eventually turns out to be benevolent).

It is arguable that by being there the Doctor has actually (unwittingly) encouraged Davros's plans to take in universal domination, as when he arrives the Kaleds do not believe in life on other planets, which makes me wonder if the Time Lords had an ulterior motive for setting these events in place...

The symbolism, imagery and political purpose of the story are all very strong then. I'm less sure about some of the internal logic - are these Kaled and Thal cities really all there is left of the two civilisations on Skaro? Has the scale of destruction been so extreme there's nothing else? If they are so close is it likely the scales would be so finely balanced?

Production is basic rather than outstanding. Some superb filming, certainly, very atmospheric and foreboding, and that brown box coat looks so right for Tom's Doctor when striding around through the mist (but how does he regain it at the end? Had the Kaleds happened to leave it in a room close to the incubation chamber?), but the studio sets are workmanlike (although they do the job, and are, I suppose, appropriately utilitarian for the story). Much of the acting is so-so, with a few exceptions.

But it ultimately remains one of the key Dr Who stories, endlessly open to reinterpretation, pivotal in terms of the series' history, with a higher than usual moral and political awareness. By Dr Who's own terms of reference, it is one of the most significant ones they ever did.