Working Title: The Planet That Slept.
Starring: Tom Baker (The Fourth Doctor), John Leeson (Voice of K-9), Lalla Ward (The Second Romana), Matthew Waterhouse (Adric).
Romana is recalled to Gallifrey, but en route the TARDIS is drawn through a Charged Vacuum Emboitment into another universe, E-Space. Landing on the planet Alzarius, the Doctor meets a group of humans who are trying to rebuild their spacecraft, which crashlanded generations ago, so they can return to their native Terradon. When Marshmen begin rising from the swamps during the dreaded time of Mistfall, however, the Doctor realises there is something amiss on Alzarius, and begins to unravel a genetic riddle which stretches back centuries.
Nineteen year-old Andrew Smith, a longtime Doctor Who and early member of the Doctor Who Appreciation Society, had been sending script ideas to the Who production office for some time when Christopher H Bidmead became the programme's producer at the start of 1980. Desperate for new writers, Bidmead came upon one of Smith's submissions, The Planet That Slept, which had been received by Bidmead's predecessor, Douglas Adams, towards the end of his tenure. In the story, the TARDIS lands on the planet Alzarius, inhabited by monstrous Marshmen which rise from the swamps during Mistfall. As the Doctor and Romana explore, a space freighter crashlands on Alzarius and the time travellers must help its crew repair the ship while fending off the Marshmen and gigantic cave-dwelling spiders.
Impressed by The Planet That Slept's striking images, Bidmead sought out producer John Nathan-Turner's consent that Smith be commissioned. Nathan-Turner agreed, with the stipulation that Bidmead carry out whatever extra work might be necessary to ensure the adventure would be ready on time. Consequently, Bidmead and Smith began working together to massage The Planet That Slept into full script form. One major addition required of the story was the character Adric, a new companion devised by Nathan-Turner and Bidmead as a version of the Artful Dodger from Oliver Twist. Played by Matthew Waterhouse, Adric's first story into production would be State Of Decay, but Nathan-Turner and Bidmead decided that this would not be his first broadcast story. Instead, Adric would be introduced in The Planet That Slept, which would be fourth into production but third aired, both to give Smith a better idea of how to write the character and to make Waterhouse appear more comfortable for the public's first glimpse of him.
Adric -- along with his brother Afrus (later changed to Varsh), who was already part of his character outline -- was a poor fit in Smith's original conception of The Planet That Slept. Consequently, it was decided to remove the spaceship's crash from the story altogether, placing the incident many generation into the past instead; at this time, the ship was also changed from a freighter to a passenger liner. This modification led to the link between the humans, Marshmen and spiders which would end up as the centrepiece of the serial. It was also decided that The Planet That Slept would form the first installment in a loose trilogy of adventures set in a small universe separate from our own called E-Space, which the TARDIS accidentally enters via a space phenomenon called a Charged Vacuum Emboitment (CVE). Bidmead devised this idea in accord with Nathan-Turner's decree that the season's stories be more tightly linked together. He also planned to use it to presage elements of the season's final serial.
The director assigned to serial 5R -- renamed to the shorter Full Circle around July -- was Peter Grimwade, who had worked on Doctor Who as a production assistant as far back as Spearhead From Space in 1969. His work as a director included The Omega Factor. Three days of location filming began on July 23rd, at Blackwater Park near Iver Heath in Buckinghamshire; another factor in Nathan-Turner's decision to hold back Full Circle to fourth in the production order was to ensure this material could be recorded during the warm days of summer. Work then moved back to the studio for a two-day block, beginning Thursday, August 8th, followed by a three-day session from Thursday the 21st. Although Smith would continue submitting ideas to the Doctor Who production office, Full Circle would be his only script to make it to the screen.