Between 1974 and 1989 the average length of a Doctor Who story was four episodes, but this had not always been the case. Stories comprising of six or sometimes seven episodes had been a regular feature of both the Troughton and Pertwee eras, and although the lengthier format often proved challenging for the writers, the budgetary implications were irresistible.
At the beginning of every new season the show would be allocated a set number of episodes with the production team then deciding how many episodes each story would be given. Longer stories meant fewer stories, resulting in each production enjoying a larger percentage of the budget; this cost cutting strategy was widely used by producers Innes Lloyd, Peter Bryant and Barry Letts.
The decision to include a two part serial in Tom Bakers first season arose from script editor Robert Holmes own personal dislike of lengthy six part stories, which he felt would inevitably contain a great deal of padding . Holmes decided that the traditional six part adventure would be split into one two part story and a four parter, the latter of which would become The Ark in Space. Ever wary of the shows limited budget, Holmes planned for the two parter to be filmed entirely on location, and that The Ark in Space would be entirely studio bound. Indeed the return of Holmes own creations the Sontaran’s was in itself another cost cutting measure designed solely to capitalise on the existing costume and space craft prop.
The writers chosen to provide scripts for The Sontaran Experiment were Bob Baker and Dave Martin, whose earlier contributions included The Claws of Axos and the shows tenth anniversary adventure The Three Doctors. The totally location nature of the adventure allowed director Rodney Bennett to take advantage of the BBC’s new Outside Broadcast (OB) video tape facilities, instead of the traditional film, this would later prove more convenient when it came to editing. One disadvantage of OB, was that it did not lend itself well to the use of Colour Separation Overlay (CSO), a visual effects process employed extensively throughout the Pertwee era. This would mean that a fully practical prop would have to be constructed for Styre’s robot servant, which had originally been conceived entirely as a CSO effect. Whether or not the CSO option would have been an improvement on the mechanical prop we shall never know, but designer Roger Murray-Leach’s rather disappointing design leaves a lot to be desired, appearing far too fragile and vulnerable to attack be taken seriously, and to be perfectly honest I’m not even certain that it’s inclusion in the story was all that necessary.
It had been Baker and Martin’s intention for filming of The Sontaran Experiment to take place at a location somewhere in the West Country, unfortunately a suitable location could not be found. Ultimately, Holmes decided that filming would take place on Dartmoor in order to take advantage of the bleak landscape and natural rock formations. The totally location nature of this story is undoubtedly one of the strengths of the production. The desolation of an Earth destroyed by solar flares and abandoned for thousands of years is convincingly depicted by the bleak surroundings of the Dartmoor National Park. The beautiful rolling heather coated hills and the rugged rocky outcrops of Hound Tor providing a visually stimulating and unique variety of backdrops for this story. The parks natural gorges were perfect for the sequences of the Doctor and Harry’s spectacular falls into the pit which were expertly and convincingly orchestrated by the shows stuntman Terry Walsh. During filming, Tom Baker slipped on a patch of wet grass, fell and cracked his collar bone. Following a trip to hospital, Baker was able to continue wearing a neck brace, which was cleverly concealed underneath his scarf, though his performance thereafter was heavily restricted, with the climatic fight sequence being performed by Walsh.
In much the same way as 1965’s The Rescue and 1982’s Black Orchid, this experimental two part story is an entertaining piece of science fiction fun, which -- if nothing -- else forms a pleasant interlude between the tense Ark in Space and the epic six part Genesis of the Daleks. Baker and Martin’s straightforward tale of a marooned rescue mission being preyed upon by a ruthless enemy is well structured, with part one establishing the characters predicament, whilst part two reveals the nature of the threat and the stories resolution. The stories title -- which was imposed upon Baker and Martin by Holmes -- spoils their only cliff-hanger and unfortunately lessens the impact of Styre’s entrance. For the most part the resolution to The Sontaran Experiment is handled well, with the Doctor and Styre’s duel culminating in the Sontaran being tricked into destroying himself, unfortunately the manner in which the Doctor dupes the Marshal into calling off a full scale invasion of the solar system is frankly absurd. Is it conceivable that the might of a Sontaran battle fleet would be stopped in its tracks on the words of their own enemy and no evidence?