What can I say about 'The Robots of Death' that hasn't been said before? Very little, actually. It is entirely deserving of its impressive reputation, and not only continues but also arguably elevates the high quality of the season since 'The Deadly Assassin'. In virtually every aspect, this story is a triumph.
The plot of 'The Robots of Death' combines a classical "whodunit" plot with an unstoppable group of killers, to produce a tense and claustrophobic story that never lets up. From the moment Chub is killed in Episode One, the tension mounts, as the human crew of the Sandminer desperately strive to find out whom the murderer is, only to be presented with the appearance of two highly suspicious stowaways in the form of the Doctor and Leela. The Doctor rapidly deduces that the robots on the Storm Mine are the real killers, but although the viewer already knows this, the emphasis then shifts to the mystery of exactly who is controlling them. It becomes clear in Episode Three, when Dask's distorted but recognizable face is seen on a monitor as he seizes control of SV7 (although admittedly I've watched this story with non-fans and they haven't recognized David Bailey's face behind that swirling red effect, so perhaps it is more obvious with foreknowledge), but by this point the pace of the story is such that it no longer matters. The pacing of the story is superb, as the death-toll mounts and more and more robots become killers, before reaching a suitably dramatic climax as the Doctor faces off against Taren Capel in his lair. To top it all off, the idea of using helium to defeat Taren Capel by altering the pitch of his voice so that the robots no longer recognise him is nicely ingenious. I have two minor criticisms of the plot, and in fact the entire story; the first is that the Doctor tells Uvanov and Toos not to let anyone onto the control deck, but doesn't bother to tell them that Dask is Taren Capel. This is obviously to maintain the surprise for any viewers who didn't recognise his face in Episode Three and haven't deduced that Dask is the villain by process of elimination, but in story terms it makes it seem as though the Doctor just can't be bothered to warn them, which nearly results in Uvanov opening the door and letting in both Dask and an army of robot killers. The second is the near-destruction of the Sandminer at the climax to Episode Two; this makes for a memorably dramatic cliffhanger, but raises the question of who is responsible. Initially, I thought that the damage to the motive units was caused accidental by Borg's death, but then one of the Vocs states that the drive linkages have been sabotaged. It seems that without the Doctor's intervention, the Sandminer would have been destroyed as a result, which is unlikely to have benefited either Taren Capel or his robots. Nevertheless, these minor flaws do not significantly detract from the story.
The script is superb, filled with great characters and excellent lines. The Doctor gets some of the best, my favourite being "You're a classic example of the inverse ratio between the size of the mouth and the size of the brain". D84 also gets his fair share, including "Would you like to use it? I cannot speak", and of course "Please do not throw hands at me". The characterisation is uniformly impressive, with both regulars coming across especially well. The Doctor is at his most authoritative and resourceful, starting out as a murder suspect but quickly gaining the trust of first Poul and then Toos and eventually Uvanov. His flippant attitude to personal danger is highlighted when he casually explains to Uvanov at the end of Episode Three that the advancing Voc has either followed Uvanov or homed in on the Doctor's communicator, cheerfully noting "It depends which one of us it's going to kill first". On the other hand, his concern for others is also strongly in evidence, as he instructs Leela to help Toos, carries Uvanov to safety whilst being chased by a homicidal machine, and befriends D84. Leela's character builds on the promise shown by 'The Face of Evil', as she is taken out of her natural environment and is thrust into an alien world that she doesn't understand; taking it in her stride, she seems to delight in learning from the Doctor and from her experiences and when threatened with danger she tackles it with the same resolution and fearlessness that she showed in her debut story. As in 'The Face of Evil', her desire to learn and the Doctor's willingness to teach, mean that aspects of the plot are explained to the audience in a way that doesn't seem contrived. And I love their first scene together in the TARDIS, as the Doctor tries to explain transdimensional engineering to her, before dismissing it as a very boring subject.
The supporting characters are also impressive, and the guest cast shines. Gregory de Polnay's D84 almost steals the show, as he (ironically) shows very human character development under the Doctor's influence, and with a robot companion not far in the series' future, I can't help wishing that he'd survived and joined the Doctor and Leela in the TARDIS. Nevertheless, he makes an impression, and is final line as he sacrifices himself ("Goodbye my friend") is touching. Uvanov, brilliantly portrayed by Russell Hunter, is another great character, starting off as a seemingly self-centered and rather mercenary character that values money over people, but proving under duress to be rather brave and heroic. In fact his attitude towards the robots in Episode Four amusingly smacks of indignation that they've had the cheek to become killers, more than anything else. David Collings, freed from the limitations of the execrable 'Revenge of the Cybermen', puts in a great performance as under-cover agent Poul, who pays the price for deciding to listen to the Doctor by having his greatest fears confirmed and losing his sanity as a result, and Pamela Salem is also impressive as Toos. All of the cast are very good, even those with relatively minor roles. Tania Rogers' Zilda could have just been another murder victim, but thanks to Boucher providing the subplot of her brother's death, she serves a greater purpose as she casts suspicion on Uvanov, inadvertently helping Taren Capel to maintain his secrecy for longer. Brain Croucher's Borg, Tariq Yunis' Cass, and Rob Edwards' Chub, despite all being killed relatively swiftly, are characters in their own right, and contribute significantly to the very human bickering in Episode One, firstly as Chub winds up Borg and argues with the icy Dask, and secondly after Chub's death as suspicion and doubt bring all the tensions in the group to the surface.
David Bailey does a very good job as Taren Capel, and his performance as "Dask" in the first three episodes nicely highlights the "verbal and physical precision" that enables the Doctor to work out that he is Capel without being obvious. Once he stands revealed as Capel, he convincingly portrays the suppressed anger and ultimately, confusion, of the character without going over the top, and of course it is suitably ironic that it is only at this stage, when his obsession with robots becomes clear, that he allows himself to show emotion. Taren Capel is a lunatic, but a lunatic with an interesting background and motivation, as it is revealed that he was raised by robots and believes himself to be one of them. Unusually for Doctor Who, he also seems to be genuinely self-delusional, rather than just a stock megalomaniac; for all that he wants to free the robots from human control, they simply come under his control instead, and it is rather ironic that he rams a laserson probe into the brain of the only robot on the Sandminer who genuinely seems to display independent thought. His death at the hands of SV7 is thoroughly appropriate; for all that he has offered it freedom, it is still a slave to its programming, and unable to recognise its voice it cannot distinguish him from any other human.
In terms of production, 'The Robots of Death' is famously rather magnificent. The actual robots, gorgeously designed in parody of the humans they serve, work very well, their polite voices as they kill people making them more sinister than for example the overtly threatening Cybermen. The set design is also excellent, providing a futuristic technological environment that is not, as is often the case in Doctor Who, sterile and functional, but designed with aesthetics in mind. The costumes (and make-up) of the human characters mesh perfectly with the sets, creating an air of decadence and indulgence. Michael E. Briant's direction is first-rate, making great use of special effects (which have aged astonishingly well) as well as inventive camera angles and scene cuts. The model work, which has probably aged the least well of any aspect of the story, nevertheless works well enough, and also meshes well with the sets. Finally, I have to mention Dudley Simpson's incidental score, one of the finest of his career on the series, which adds to the tension and drama considerably.
After three such strong Doctor Who stories in a row, and particularly one as near-flawless as 'The Robots of Death' it is almost unfeasible to think that the production team could maintain this level of quality, let alone top it. Nevertheless, the story that follows is not only my highlight of the season, but also my favourite Doctor Who television story of all time