Terry Nation is possibly Doctor Who's most erratic writer. On the one hand he is capable of writing classics such as 'The Mutants', 'The Dalek Invasion of Earth', 'The Daleks' Master Plan' and 'Genesis of the Daleks', whilst on the other hand he is capable of writing such balderdash as 'The Keys of Marinus', 'The Chase', 'Planet of the Daleks', and, unfortunately, 'The Android Invasion'. Apologists for this story might argue that it seems worse than it is alongside the other stories of Season Thirteen, but personally I think there's so much wrong with it that placing it next to any other story, no matter how dire, is going to amount to little more than trying to polish a turd.
'The Android Invasion' suffers from more plot holes than any other Doctor Who story I can think of. First of all, we have the replica of Devesham on Oseidon. This is immensely detailed and extremely elaborate, which raises the question, what exactly is the point of it? To explain what I mean, allow me to recap Styggron's plan. The Kraals intend to invade Earth and wipe out mankind using a virus. The virus isn't airborne and it kills its victims within seconds or minutes, which would limit its spread immediately, since anyone infected with it wouldn't have time to travel very far before dying. Metres, if they are lucky. Therefore, Styggron's androids are intended to "disseminate" the virus. In addition, note that Styggron insists that the extermination of mankind will take place within three weeks. Therefore, the androids will have to transport the virus to all parts of the planet within that time and physically expose everyone on Earth to it. This is, clearly bollocks; firstly, there are only a handful of androids, and secondly as soon as whole areas started dying in one go, quarantines would be enforced. Since there is no evidence that Styggron has facilitates on Earth to make new androids, this means that a group of androids who resemble the inhabitants of one small village are expected to evade quarantines without being noticed, which is also bollocks, and in case anyone is thinking of pointing out that they are allegedly indestructible, allow me to point out that this is twaddle, since Sarah electrocutes one (and their faces fall off very easily if they trip up). Even if we assume that this is possible, the androids would still have to spread out from Devesham on arrival, which raises the question of why Styggron establishes an elaborate program of training that involves the androids spending an afternoon in the local pub. The point is, the only possible reason for the needlessly elaborate Devesham mock-up would be if the Kraal androids were intended to infiltrate Devesham by replacing the inhabitants and then spend some time there gathering information. Which they aren't. Indeed, not only that, but they successfully replace the entire personnel of the Space Defence Station within minutes of arriving. The only remotely plausible explanation that is actually consistent with the witless plot is that the training ground allows them to become familiar with the layout of Devesham and the Space Defence Station, which in any case is provided to Styggron by Crayford. Some kind of map might have been easier
In addition to these gaping plot holes, if Styggron wants to use the androids to wipe out mankind, why doesn't he just drop androids all across the planet from orbit, instead of bringing them all to Devesham? If he's so clever, why doesn't he just create an airborne virus? If he can't, why doesn't he just fill a couple of pods with the virus and dump it in the ocean, since Nation appears in any case to have misunderstood the difference between the words "virus" and "poison". The number of unanswered questions in this story are astounding; if the brain patterns taken by Styggron from humans are as detailed as he implies, why does the android Sarah not know that the real Sarah dislikes ginger pop and that she left her scarf with the Doctor? Are the dogs used to chase the Doctor and Sarah real dogs, and if so how did they get to Oseidon? If not, what are they for? If they are androids but are capable of following the tracks of the Doctor and Sarah, then why can't the other androids do the same? Waste of time making robot dogs, frankly. Why does the otherwise insanely detailed fake Devesham have stupid mistakes like the calendar with only one date in it? Why don't the androids in the pub grab Sarah in Episode One? If they're intelligent enough to realize that she could be part of some test, surely they're intelligent enough to bother to just hold on to her whilst they check with Styggron? Why, if most of the androids arrive at the pub in a truck before being properly activated, are some androids inside pods dotted around the village? Did they get bored and decided to play hide and seek? In Episode One, when Styggron tells Crayford that there might be rogue unit on the loose, does he catch a flicker of movement at the end of the corridor and immediately dive through a door to get at a gun? He can't possibly see that it is a stranger, and the androids are bulletproof. Well, probably: Styggron's claim that they are invincible is, as noted above, twaddle. To top it all off, the story ends with yet another notorious gaping hole as the Doctor uses a powerful electromagnetic field to jam the circuits of every android in the area, but then somehow manages to use his own android against Styggron. Apologists for this story might argue that this makes the Doctor look very clever, but given that he ahs only a few minutes in which to equip the android with a formidable array of shielding and reprogram it as well, I would argue that it makes Terry Nation look like a bit of an arse.
Amongst all this rubbish, is there anything good about 'The Android Invasion'? Not really, no. The Kraals look quite good, but Styggron is basically a standard ranting megalomaniac with a mad plan, a line in gloating, and stupid dialogue ("Resistance is inadvisable!" Come back Professor Zaroff, all is forgiven ). Chedaki is voiced by Roy Skelton, who seems to have forgotten which of his roles he's in, as Chedaki sounds like bloody Zippy from Rainbow. Milton Johns is a fine actor, but Crayford is a ludicrous character; how on Earth he got the job of an astronaut if he's so paranoid that he assumes he's been deliberately abandoned when something goes wrong, and then agrees to help space Rhinos invade is a mystery, and then of course there is the notoriously stupid plot device of him never having looked under his eye-patch - does the man never wash?
The direction is adequate, the design uninspiring; the interiors of the Kraal base are forgettable and the spiky-bottomed doors just look daft. The whole set up in Episode One of the quite village with its inhabitants acting strangely is promisingly sinister, but delivers manure. Even the title is rubbish, suffering from the same basic weakness of 'Revenge of the Cybermen' in that its title undermines the mystery behind the first episode from the start. The regulars are fine; Tom Baker and Elizabeth Sladen are capable by this point in the series of playing their respective roles with consummate ease, and both tackle the feeble script well. John Levene and Ian Marter are also both their usual reliable selves, but they get little to do and it is therefore a shame that their last appearance in Doctor Who is in this story rather than the marvellous 'Terror of the Zygons'. Nicholas Courtney gets a particularly lucky escape in that respect, with the character of Colonel Faraday created as a stand in; Patrick Newell does well with what he's given, but the script paints him as a buffoon and the Brigadier had quite enough of that in 'The Three Doctors'.
I'll end by pointing out one last plot hole; the Kraal fleet is poised to attack, but is never mentioned again after Styggron's death. In Episode Two, Chedaki tries to convince Styggron to abandon the androids, arguing that they are dangerous and that the Kraals can conquer Earth without them. Why then, do they not invade? The answer, and indeed the answer to all the plot holes in 'The Android Invasion' is actually quite simple: Chedaki and Styggron are lovers, but Chedaki is rather submissive; keen to please his completely loopy boyfriend, Chedaki humours his occasional plan to invade other planets even though they are ill thought out and obviously won't work. Once Styggron dies, Chedaki breathes a sigh of release and decides to quit whilst he's ahead, and/or goes home to Oseidon because he's too distraught to lead an invasion. Makes more sense than what we see on screen, anyway