What's Wrong With... The Keys of Marinus

Were you to have asked designer Ray Cusick what went wrong with The Keys of Marinus then he would have pointed the finger squarely at the writer, Terry Nation, and the director, John Gorrie.
He claimed that the latter did not show any interest in the design aspects of the show, whilst the former presented him with the challenge of devising different sets and props almost every week of the six episode run. Cusick was on record as saying this was his least favourite Doctor Who story he worked on.
The problem was that Nation had been so impressed with the way that his Dalek story had turned out that he thought the BBC designers could do anything. However, that story had relied on a number of sets which would be seen over a number of weeks - their costs spread accordingly. With his new story, written in a hurry after other scripts had hit problems, Nation came up with a quest adventure, which would switch locations every week as the TARDIS crew went to different places in search of the titular keys.
There wasn't any more money available in the budget for this show than any other in the season (save for the start up costs for the very first episode and its remount). Episodes 2, 3 and 4 all have sets and props which don't feature in any other episode. It's a wonder Cusick managed to deliver so many different sets in the end, although you can see where corners had to be cut. For instance, the central area of Arbitan's pyramid where the Conscience machine is located features a wonderful transparent dodecahedron prop, but for the background Cusick had to resort to plain black drapes. The ice tunnels in the fourth episode are clearly made from ordinary rock walls covered in cling-film to simulate ice.
The plumbing in the same episode, which keeps the key locked in a block of ice, looks pretty low tech, like the sort of thing which homes of 1964 would have had. Cusick was actually reprimanded by his boss for using expensive materials for the city of Morphoton, which had to appear both in a dilapidated state and in a luxurious form as seen by the hypnotised travelers. The other sets in this episode appear very basic as a result, with black drapes once again used for the background to the chamber where the Morpho brain creatures reside. The rotating statue in the jungle episode clearly has the arms of a studio-hand sticking out of it.
Later, when we get to the city of Millenius, the courtroom seems to have used up the budget, as all the other parts of the city we see are very spartan. The cupboard where valuable exhibits are held appears to be an ordinary wooden cabinet, locked by a small key, rather than anything which hints at high security.
As mentioned above, this story was a rush job as Nation was supposed to be working on a historical story set in India during the Mutiny - often referred to as 'The Red Fort'. A story by Malcolm Hulke about an alternative Earth on the far side of the sun - possibly to have been called 'Beyond the Sun' - was continually being pushed back as script editor David Whitaker had problems with it.
Nation was called in to write a replacement as he was know to be a quick and dependable writer. He had written his Dalek story an episode a week. Rather than devise a single story that would hold up by itself for 6 weeks, he opted for the quest structure, as this allowed him to write a number of smaller adventures which wouldn't stretch to full stories on their own.
His rush leads to a number of plot problems - starting with the entire premise of the story.
The Doctor and his companions decide that they are not going to help Arbitan fetch the keys, so he puts a forcefield around the TARDIS to coerce them into doing what he wants. His machine - the Conscience - affects peoples' minds, making them refrain from crime. The Doctor disagrees with the method to achieve this, as he states at the conclusion. However, rather than stay and fight against Arbitan and regain the TARDIS, the Doctor gives in - even though it means he is helping a man who is going to manipulate the minds of an entire planet.
Arbitan talks as if he created the machine, even though it is 2000 years old. All the inhabitants of this planet must be extremely long-lived, as Yartek is supposed to have overcome the Conscience's influence 700 years ago. Arbitan hid the keys around Marinus so that they wouldn't fall into the wrong hands - which is exactly what has happened to them.
How did Yartek overcome the Conscience, when it should have stopped him even wanting to do such a thing? Why has it taken Yartek 700 years to launch a proper assault on Arbitan's island? It's also a bit of a coincidence that he turns up just when someone has arrived who might actually succeed in retrieving the keys, when previous attempts have all failed. What would he have done if the Doctor's party hadn't been sent off to collect them, bearing in mind that he has just had murdered the only person who knows how to make new keys?
What is it with the travel dials? They do whatever the plot wants of them, rather than work in any logical fashion. Barbara goes on ahead of the others by only a few seconds, but when we next see her she has had time to get settled in the city of Morphoton, learn all about it, and had a dress run up.
Later, the dial takes Ian to the very room where the fifth key is located, yet all the other times the dials have left people miles away from the keys. And why does only Ian arrive in the museum vault? Where do the others arrive?
Taking of the museum vault, why has Eprin not collected the key sooner? The citizens of Millenius say that they are quite prepared to hand it over to Arbitan or one of his agents - so why didn't Eprin just ask for it on his arrival?
It's the same with mad old Darrius in the jungle. Why invent deathtraps when he is expecting Arbitan to send someone for the key?
In the fourth episode, why doesn't Vasor just kill Ian while he's unconscious? Instead, he has to be over elaborate and send him off with a bag of meat in the off chance that the wolves will get him. What makes he think the travel dials and keys are valuable? As a fur trapper living alone in the mountains wouldn't their clothes be of more use to him?
Likewise Eyesen and Kala and their plan to steal the key from the museum. Who did they hope to sell it to? Eyesen puts on a black mask when he breaks into the room to steal the club which has the key hidden inside it. A smart move you might think, but he's still wearing his distinctive uniform.
It's never explained how long the Conscience has been deactivated. It must be not working, for Vasor to be a murdering rapist and for Kala, Aydan and Eysen to be killer-thieves. Millenius has also had time to set up an advanced criminal justice system.
Who are the Ice Soldiers who guard the fourth key? Did Arbitan employ them to be frozen for centuries? When Terrance Dicks wrote a book in the late 1970's called The Adventures of K9 And Other Mechanical Creatures, he claimed that the Ice Soldiers were robots. We can clearly see that they are just men, and one of them screams when he falls down a crevasse - so not robots.
Something else which went wrong with The Keys of Marinus was that the new aliens - who are inconsistently called Voords and Voord as a plural - failed to become the new Daleks, despite a lot of press coverage. This might be because they only appear in the first episode, and then again in the last quarter of the sixth episode. This won't be the last time that Nation fails to come up with a new marketable monster. The Voord never returned to the programme though they did appear in other media such as the Dr Who Annual and a series of collectable cards.
Perhaps the fact that one of them trips over his own flippers in the sixth episode showed the limitations of the Voord as on-going foes for the Doctor.
Last but not least, we have a couple of great Hartnell fluffs. There might have been more, but he went on holiday and so was written out of episodes 3 & 4.
In the first episode the Doctor is arguing against the sea being frozen:
"No, impossible in this temperature. Besides, it's too warm...".
A short time later he berates Ian for not giving Susan his boots: "If you'd been wearing your shoes you could have lent her hers".
Returning from his holiday he has another fluff as, in the fifth episode, he gives us: "I can't improve at this very moment... I can't prove at this very moment...".