Inspirations - Planet of the Daleks

1973's Planet of the Daleks was Terry Nation's first solo contribution to the series since 1965, when he had penned Mission to the Unknown. He had come up with many of the concepts for The Daleks' Master Plan, though it was mostly scripted by Dennis Spooner, Donald Tosh and Douglas Camfield.
David Whitaker had then taken over writing for the Daleks, before they were removed from the programme altogether. This story also marked the first time that an adventure specifically designed to feature the Daleks had been written since Evil of the Daleks, since they had only been a late addition to what became Day of the Daleks.
As we mentioned last time, this story forms the second half of a bigger anniversary tale. Frontier in Space had shown the background to the invasion which the Daleks intended to launch on the back of a manufactured war between Earth and Draconia. That story had ended with the Doctor badly wounded, and using the TARDIS telepathic circuits to ask the Time Lords for assistance - guiding him after the departing Dalek spaceship.
One of the first problems we hit is that the new storyline pretty much dispenses with that set-up.  There is no dialogue concerning the events of the previous 6 episodes - no mention of the Master or of the Draconians at all. The Gold Dalek is absent from Spiridon. Nation seems to have simply set out to write his own story, with no regard as to how it fitted with Malcolm Hulke's narrative. The Episode One cliffhanger even has the Doctor shocked to find that there are Daleks on this planet - even though he specifically asked the Time Lords to take him to the Dalek invasion base. What few links there are we can safely attribute to Terrance Dicks.

What we do get is Terry Nation ignoring everything that has happened in Doctor Who since he last wrote for it. This is mainly down to the fact that he has obviously never kept up watching it, being too busy working on various ITC Spy-Fi series or failing to get the Daleks a series of their own.
Never one to overthink an idea, he delivered to Barry Letts and Terrance Dicks a greatest hits package featuring elements of his old 1960's stories. He originally titled it "Destination: Daleks", and so set it on the planet Destinus. You'll recall that he was the chief culprit when it came to naming planets after their chief characteristic. Skaro was scarred by war, Aridius was dry and arid, Marinus had its acid sea, Mira was swampy, and Desperus was full of desperate criminals. Nation also gave each episode its own title, unaware that this practice had died out in 1966.
The story begins in the TARDIS, and Nation has some outdated views on just what the Doctor's space / time machine exactly is. To him, it is just a glorified spaceship. Back in The Chase, he had the Doctor claim that they would all suffocate if he suspended the ship in space for any great length of time - suggesting that it carries a finite oxygen supply. The Monk is later congratulated on getting round this, by developing a form of "drift control". In the opening episode of this story, the TARDIS becomes encrusted with a mass of vegetable spores - which is enough to cut off its oxygen supply. Nation thinks that the ship has to draw its air from the outside. But how can it then run out of oxygen? If air can't get in, then where does the air that was in the ship escape to? Or did the comatose Doctor manage to snore it all up? (Maybe - Pertwee did have a mighty nose). We see a hitherto unseen secondary oxygen supply - three cylinders of air which are clearly not bigger on the inside. Two of them are empty and the third has only a tiny amount left in it.
The scanner was definitely colour in The Three Doctors, but now it is black & white. Perhaps the Doctor is trying to save money. (Cue very old joke about buying a black and white dog cos the licence is cheaper...).

The Doctor is rescued by a party of Thals - the race who have never featured in any other Dalek story since the first one he wrote. They are led by Taron - a name well known to Nation fans as he uses some permutation of it in most of his writings. Terry N becomes Taron, Tarrant and so forth. And Taron's love interest, Rebec, gets her name from Nation's daughter Rebecca.
It turns out that these Thals know all about the events of that first Dalek story, as they have heard of the Doctor and the TARDIS, and know that he had three travelling companions - whom the Doctor then name-checks.
We should point out that Spiridon is a jungle planet - at least while the script needs it to be. Nation loves his jungles. The forest on Skaro was never called a jungle, but that is what it looked like, and we had a lengthy march through a mutation-filled swamp. Once we get to later Nation-Dalek stories, he uses jungle settings for Mechanus, Mira and Kembel. Nation was a huge fan of cinema in his youth, skipping school during the war to watch movies as often as he could get away with it. He clearly liked war movies, as he uses tropes from this genre throughout his work, and it would not be much of a guess to say that he loved war films set in jungle terrain - with John Wayne et al fighting the Japanese. There is a lot of jungle guerrilla warfare going on in these six episodes.
Meanwhile, Jo, whose idea of jungle-suitable clobber includes a rain mac over a padded jacket and woolly gloves, has gotten herself infected by the nasty Spiridon plant life - the same ones who smothered the TARDIS. They are named Fungoids - the exact same term used by Ian Chesterton to describe the massive mushroom-shaped plants on Mechanus.
Nation also likes his hostile plant life. Apart from the Fungoids, he also had strangling vines in the third episode of Keys of Marinus, and the Varga Plants in Mission to the Unknown. The Slyther had a touch of the vegetable about it come to think about it. As well as the spore-spitting Fungoids here, we also get the Eye-Plants, and another plant which sends tendrils out to grab any unwary Thal soldiers who may be in the vicinity.

The natives on this planet are invisible, and the Daleks are studying them so that they too can become invisible. Again, this isn't new for Nation. He had previously introduced the Visians of the planet Mira, who were also invisible.
Some other recycling includes:
A Thal falling in love with the Doctor's companion (as with Ganatus and Barbara in The Daleks).
From the same story we have one of the characters hiding in a Dalek casing, and just as we think they have been blown up by real Daleks it transpires that they got out in the nick of time.
Then there is the escape up a shaft (a lift in the first story and an air duct here), with a lone Dalek in pursuit - which is destroyed when someone drops something down on top of it.
Also from The Daleks we have speeches about war / pacifism - between the Doctor and Codal and later the Doctor and Taron here, and between Ian and Alydon in the earlier story).
This is the first time since that The Daleks that one of the regulars is shot and wounded by a Dalek, producing paralysis in their legs (Ian then, the Doctor himself now).
From The Dalek Invasion of Earth we get the use of plague as a weapon. Here, the Daleks intend to release a plague into the jungle which will destroy all life not immunised against it. Plague will come to be an obsession for Nation, as we will see when we look at later stories by him, and of course he will later write a whole series about a plague-decimated Earth (Survivors).
Two earlier Nation-Dalek stories featured the Doctor locked in a cell and having to use his scientific knowledge to work out the means of escape.
From Mission to the Unknown we have the secret mission going wrong when the ship crash-lands (Marc Cory's then, the Thals' now), as well as the Daleks using their firepower to destroy a whole spaceship.
An unintended homage to Evil of the Daleks, for which Nation can't be blamed, is the inclusion of Louis Marx toy Daleks in the grand finale. (The person who can be blamed is Cliff Culley, who was also responsible for the dinosaurs in Invasion of the Dinosaurs, and the Action Man tank in Robot).

Even the Peter Cushing movies get a nod, as one of Nation's Dalek props from the films gets a black and gold respray (plus jam jars on its dome and a torch stuck on its eye-stalk) to become the Dalek Supreme. Nation hated the idea of an Emperor Dalek - his lead villains were always Supremes. The first appearance of the Supreme is even accompanied by a little music cue from the first movie, courtesy of Dudley Simpson. From The Daleks' Master Plan we get senior Daleks exterminating their underlings when they screw things up.
We mentioned above that this is a jungle planet - but only when the script needs it to be. In the second half of the story the idea of an ice volcano is introduced, so Spiridon suddenly gets an icy location wasteland right next door to the hot and steamy studio jungle.
The word allotrope is mentioned - specifically an allotrope of ice. This word was first coined by a Swedish scientist in 1841, to describe how some chemical elements can exist in different physical forms. The most obvious one is carbon, which can be coal, graphite or diamond. Water doesn't count (even though it can be gas, liquid or solid) as it isn't an element but a compound (hydrogen and oxygen).
The liquid ice proves to be the means of defeating the Daleks, as a Thal bomb is used to blow a hole in the chamber where the Dalek army is stored, causing it to flood with ice. Earlier, the Doctor claimed that extreme cold kills Daleks, yet this freezing deluge is said to only put the army back into hibernation.

Whereas Barbara and Ganatus spent a lot of time together on Skaro, long enough for romance to realistically blossom, Latep seems to fall for Jo after about 5 minutes. The poor boy seems to think that Jo will give up TARDIS travel and go live with him on Skaro on the strength of their brief time together.
 Jo then shows a remarkable knowledge of the TARDIS controls, as she is able to summon up a picture of the Earth on the scanner. Why? - because that's where she wants to go.
Next time, Jo returns to Earth, and this time she is staying put as she meets a younger, sexier version of the Doctor. The Doctor is envious, but it is other people who turn green...