Written by Malcolm Hulke, Colony In Space, sees the Doctor visit an alien planet for the first time since his exile to Earth began at the conclusion of The War Games.
You'll recall that the exile scenario was inherited by producer Barry Letts. He and script editor Terrance Dicks could see how this limited their story-telling possibilities, and so resolved to find a way for the Doctor to get back into outer space at the earliest opportunity. But how to do it? An experiment with the TARDIS had sent the Doctor off to a parallel universe at the end of the previous season, but this trick couldn't be played every time.
Dicks had co-written the Doctor's trial, with Hulke, and he knew that one of the reasons he had been exiled was because he tended to get involved - whereas the Time Lords refrained from interference.
Was it that they never interfered, as a point of principle, or was it that they did not like to be seen to do it? The idea then formed that the Time Lords would occasionally get involved in the affairs of other planets - but only through some other agency. With the Doctor excluded from Time Lord society, he could be deemed a free agent. The Time Lords could send him on the odd mission - directing his TARDIS by remote control. For the first of these special missions, the problem would be one that directly impacted on the Time Lords themselves.
They have been seen as powerful and secure enough for other civilisations to entrust them with their secrets. That trust in their abilities would be seriously undermined if someone unscrupulous were to steal these secrets and attempt to use them for their own gain - especially if that someone was one of their own kind.
The story opens with what we can assume to be members of the High Council of Time Lords discovering that one of their files has been stolen by the Master. With the benefit of hindsight, this might well be the Celestial Intervention Agency. They need to get this file back - or at least stop the Master getting his hands on whatever secret the file relates to.
Meanwhile, at UNIT HQ, the Doctor thinks he has fixed the dematerialisation circuit. We have already been told that the Master is going to be involved, and at UNIT the Brigadier thinks that he may have a lead to his whereabouts. The Doctor states that a previous sighting proved to be the Spanish Ambassador. This is an in-joke, as Roger Delgado played the recurring role of the Spanish Ambassador, Count Bernardino de Mendoza, in the 1961 ITC series Sir Francis Drake.
Jo follows the Doctor into the TARDIS, and here we hit a bit of a problem. It is clear that Jo has never been inside the ship before, and does not believe that it can travel in Time and Space.
So, at no point since Terror of the Autons has she been invited in, or taken a sneaky peak when the doors were open. Bear in mind that one school of thought holds that a whole year passed between Terror and The Mind of Evil. Jo has also seen the TARDIS dematerialise - in just the last episode.
There is also the issue of why the Master was messing about with the Axons when he could get his hands on the most powerful weapon in the universe.
This has led some fans to consider swapping the running order - placing this story before The Claws of Axos. I've watched it like this and it works - the only slight hiccup being the Doctor stating that the Master will "have left Earth by now" at the beginning of Claws - implying there's just been an Earthbound encounter.
The TARDIS suddenly comes to life, and the Doctor urges Jo to leave, but she remains and the ship departs.
The idea that the Time Lords have a devious streak starts with this story. Not only are they breaking their own laws by using an agent to intervene on another planet, but they decide not to actually tell him anything about where he is being sent, or why. You would think a successful mission should begin with a comprehensive briefing. Perhaps the Time Lords have been observing the Doctor's travels for quite some considerable time before finally reeling him in, and have realised that he works best when confronted by a mystery - forcing him to think on his feet.
The TARDIS lands on the desolate-looking planet of Uxarieus, and here a number of inspirations can be felt.
Initially the Doctor and Jo encounter a party of colonists who have fled from an overcrowded and polluted Earth to begin a new life as farmers. This is the first time since Planet of Giants that the series has attempted to consider ecological issues. We're still a couple of years away from the BBC sitcom The Good Life (it began in 1975), but concern about the environment and the desire to lead a greener, more simple and self-sustaining lifestyle had been growing since the mid-1960's. This was a reaction to the aggressive marketing of consumerism. If you wanted something new - and you were always being told you needed something new - then it was easy enough to throw out the old one and buy the latest model. Products were being manufactured with an in-built obsolescence. Towns and cities were struggling to cope with the amount of rubbish that was being thrown away, whilst TV screens showed adverts about keeping the countryside tidy. The "Keep Britain Tidy" campaign - still going strong - developed out of the British Women's Institute in 1955, designed to keep the country litter-free.
At this stage in the series, Jo is still a little nice-but-dim - thinking that the colonists left Earth in a spaceship in 1972. Mind you, Hulke will later create a group of people, who really ought to have known better, who will believe such a voyage feasible in 1974.
The colonists have found that the soil will not support their crops, and their venture may be doomed to fail. Added to this, they have now found themselves under attack from some previously undiscovered savage dinosaur creature. This proves to be fakery, created using a holographic projection of an ordinary iguana, coupled with a mining robot equipped with false claws. The people behind this are IMC - the Interplanetary Mining Corporation. They represent polluting Big Business.
For Hulke, they are the bad guys, and he clearly favours the simple farmers. This reflects his strongly felt political views. He was a card carrying member of the Communist Party of Great Britain, though he fell foul of the organisation when they suspected him of spying on their activities for the authorities. He had called the Home Office from the CPGB's offices on a personal matter - relating to his naturalisation papers - and this had been noted on the phone bill. He left the party in the 1950's, possibly due to his objections to Moscow's invasion of Hungary, but retained strong left wing beliefs.
The planet on which these two sides confront each other is not uninhabited, however. which leads us to see another inspiration lurking beneath the surface. The "Primitives" can be seen as a parallel for the indigenous peoples of North America, or indeed any country which has suffered under Western colonialism. The actual plot for much of the story plays out like a Western, with the natives (Green , rather than Red Indians, to use the parlance of the early 1970's) being forced off their land by settlers, who then come under attack by well-organised claim-jumpers. We have a number of shoot-outs between the settlers and the miners as they jockey for supremacy. The IMC commander - Dent - decides to permit an Adjudicator to be called in to determine who should get the rights to this planet. In the earliest days of the judicial court system, smaller towns and villages did not have their own local legal representatives. Justice tended to be meted out by whoever owned the most land in the district. The concept of assizes and circuit judges was created. Prisoners awaiting trial languished in jail until the circuit came round, roughly four times a year.
When the Adjudicator does turn up, rather quickly one might add, it turns out to be the Master in disguise. Viewers watching this story when first broadcast, an episode a week, might just have forgotten that the Master was the one who triggered the Doctor's mission in the first place, and so his turning up was supposed to come as a surprise. At least we have gone a few episodes without him.
Once the Master has arrived on Uxarieus, the reason for the Doctor's mission can come to the fore. The colonists and miners are still fighting each other in the background, but we now learn that the Master is interested in the city of the Primitives. The Doctor has already been there, after Jo was captured by the Primitives, and he knows that there was once a great civilisation on this planet, which decayed. The elders of the city, possibly a different species to the Primitives, have reverted to superstition - carrying out human sacrifices to their technology. One of the civilisation's leaders still exists - the diminutive Guardian.
This takes us into Erich Von Daniken territory. He is the most famous proponent of the Ancient Astronauts theory, wherein many of the great monuments of prehistory can only be explained by the intervention of visitors from another planet. There will be a lot of this through the course of 1970's Doctor Who. We'll take a closer look at it when we get to Death to the Daleks, where it is more explicitly referenced.
The secret which the Master gained from the stolen file concerns a terrifying weapon - which we'll call the Doomsday Weapon, as that is the title under which this story was novelised. Apparently the Crab Nebula was created when the device was tested. This astronomical phenomenon was first spotted by the Chinese around 1054, when they witnessed what we now know to have been a supernova. This allows us to see that the Guardian's civilisation was at its peak 1400 years before the events of this story.
That's 1400 years in which the Master could have come along and gained the device for himself, instead of waiting until there were two lots of squabbling humans in the way to complicate matters. Why didn't he just turn up a couple of years earlier? Doesn't he have a time machine?
If the Master can be relied upon to suddenly change his plans on a whim, then the Guardian can trump him. He's been guarding the weapon for centuries, but after a brief chat with the Doctor, and one look at the Master, he suddenly decides to commit suicide and self destruct the weapon - blowing up all his own people while he's at it.
It was radiation from the device which was preventing the colonists' crops from growing, and the Doctor seems to think that all that radiation will disappear overnight now that it's gone.
IMC have been overpowered by the settlers, and there is a proper Adjudicator on the way. Now, the reason Dent was happy to call one in in the first place might imply that they tend to side with Big Business, or be open to corruption, so what makes the colonists think that the real one will be any different?
What happens next doesn't concern the Doctor, as he and Jo get back into the TARDIS and return to UNIT HQ, landing just seconds after they left. Good job the TARDIS materialised in the opposite corner of the lab from where it started, otherwise the ship would have landed on top of the Brigadier. (It's only since 2005 that we see that the ship materialises around people and objects).
Next time: The Devil rides out in a quaint English village, which someone had the foresight to name after him. Can you guess who the new vicar of Devil's End might possibly be...?