Production Code: 4B
First Transmitted
1 - 22/02/1975 17:30
2 - 01/03/1975 17:30
Plot
The Doctor, Sarah and Harry arrive on a desolate and apparently deserted Earth to discover that a group of shipwrecked astronauts from a human colony, GalSec, have been lured there by a fake distress call. One of their number, Roth, tells Sarah of an alien conducting gruesome experiments on him and his crewmates. The alien turns out to be a Sontaran, Field-Major Styre, who is compiling a report on human physical and mental capabilities as a prelude to an invasion of Earth.
The Doctor challenges Styre to unarmed combat. The Sontaran agrees but is quickly weakened in Earth's unfamiliar gravity. Harry meanwhile enters Styre's ship and uses the Doctor's sonic screwdriver to remove the vital terullian diode bypass transformer, so that when the alien returns there to revitalise himself he is drained of all his energy and destroyed.
The Doctor sends a message to the Sontaran fleet, warning them that without Styre's report they cannot invade.
Episode Endings
The alien emerges from its ship and removes its helmet. It is a Sontaran.
The Doctor, Sarah and Harry leave Earth via the transmat with the intention of returning to Nerva.
Roots
Robot Monster.
Planet of the Apes.
Dialogue Triumphs
Harry : "Doctor! I thought you were dead."
The Doctor : "Not me" [He holds up a piece of metal.] "Piece of the synestic locking mechanism from Nerva's rocket - popped it in my pocket."
Harry : "'Fortuitous"
The Doctor : "Foresight. You never know when these bits and pieces will come in handy. Never throw anything away, Harry." [He throws it away.] "Now, where's my five hundred year diary. I remember jotting some notes on the Sontarans... It's a mistake to clutter one's pockets, Harry."
Vural : "Clock expert?"
The Doctor : "Horologist, actually, and chronometrist. I just love clocks: atomic clocks, quartz clocks, grandfather clocks... Cuckoo clocks..."
Dialogue Disasters
Harry : "I feel a bit like a Morse message: slightly scrambled."
Continuity
Sarah initially believes Field Major Styre of the Sontaran G3 Military Assessment Survey to be Linx (The Time Warrior). She says that they are identical, which they aren't (Styre's face is paler, squatter, and lacks bristles, and he has five rather than three digits). [As with the tall Sontarans of The Two Doctors, it seems clear that, although a cloned species, a degree of morphological diversity is present. That there is also mental divergence is obvious or else the military ranking system is meaningless.]
The main Sontaran military leadership group is known as the Grand Strategic Council. Styre uses a 'pistol' rather than the typical Sontaran wand. A terrulian diode bypass transformer is a vital part of the 'recharging' equipment used by Sontarans, allowing them to 'feed on pure energy'. Sabotage of this component proves fatal for Styre. The Sontaran robot is also powered by terrulian.
The Doctor thinks that his 500 Year Diary has notes on the Sontarans in it [made, despite partial memory loss, after the events of The Two Doctors?]. The sonic screwdriver is used to repair the transmat spheres and to disable the robot. Mention is made of the vast animal/botanic section on Nerva.
Location
Earth, possibly 'London', in the same period as The Ark in Space.
Future History
By the time of The Ark in Space, Earth has been without any form of animal life for around 10,000 years. However, Earth has been habitable for several thousand years. [The solar flares are not those mentioned in 'The Trial of a Time Lord'.] Nerva, 'the lost colony', has never been found, and has become a legend [as it's in Earth orbit it presumably has some stealth capability].
Other Earth colonies, such as Galsec, have established large empires (such peoples are perhaps the regressive elements mentioned by Vira in The Ark in Space). With humans in control of around half of the galaxy, many of the empires have no time for 'Mother Earth' philosophies (cf. Planet of Evil). It is commonly believed that Earth is still uninhabitable.
Trivia
This was the first story to be recorded with no interior scenes.
Kevin Lindsay makes his last Doctor Who appearances, playing Styre and the Sontaran Marshal. He died not long afterwards as a result of a long-standing heart condition.
The GalSec astronaut Krans is played by Glyn Jones, the writer of the season two story The Space Museum.
Tom Baker broke his collar bone during the making of this story, and he is consequently doubled by Terry Walsh in many of the scenes where the Doctor is required to move or engage in physical action.
Technobabble
Styre's terrulian diode bypass transformer.
Goofs
Obvious use is made of stand-ins during the fight with Styre.
During the fight the Sontaran's head is knocked sideways.
Why only send one Sontaran? (Numbers are surely not at a premium in a cloned race?)
And why is Styre experimenting on humans prior to an invasion of Earth when the planet is depopulated anyway?
Fashion Victim
Sarah in her yellow mac and woolly hat? At least it's practical (cf. Jo Grant).
Cast & Crew
Cast
The Doctor - Tom Baker
Harry Sullivan - Ian Marter
Sarah Jane Smith - Elisabeth Sladen
Erak - Peter Walshe
Krans - Glyn Jones
Prisoner - Brian Ellis
Roth - Peter Rutherford
Styre / The Marshal - Kevin Lindsay
Vural - Donald Douglas
Zake - Terry Walsh
Crew
Director - Rodney Bennett
The Sontaran Experiment