State of Decay is the fourth serial of the 18th season in the British science fiction television series Doctor Who. Written by longtime Doctor Who writer Terrance Dicks and directed by Peter Moffatt, it was first broadcast in four weekly parts on BBC1 from 22 November to 13 December 1980. The serial is the second of a loosely connected trilogy set in the universe of E-Space, and follows the Fourth Doctor (Tom Baker), his companion Romana (Lalla Ward), and stowaway Adric (Matthew Waterhouse) land on a planet where a medieval village is controlled from a tower by the Three Who Rule, three vampiric lords who descend from the crew of a crashed Earth spacecraft.

Dicks originally outlined State of Decay in 1977 for the show's fifteenth season, under the title The Witch Lords, before it was shelved by the BBC. Incoming producer John Nathan-Turner revived the concept and commissioned new scripts from Dicks, who often came into conflict with new script editor Christopher H. Bidmead over the latter's insistence on adding more science fiction elements to the story. Nathan-Turner chose Peter Moffatt, an experienced director with a reputation for punctuality, to direct. Filming for the serial began in April 1980 at Burnham Beeches in Buckinghamshire and continued at the BBC TV Centre throughout May. The shoot was marred by tension between the cast, particularly as a result of Waterhouse shooting his first serial and problems between Ward and Baker due to their romantic relationship. Several model shots were used for the serial, while Paddy Kingsland composed the score, which was recorded on synthesizers.

The serial received relatively low viewership at around five million viewers per episode, partially due to competition from ITV's concurrent airing of Buck Rogers in the 25th Century, but performed better in its Appreciation Index score. The negative depiction of vampire bats in the serial prompted outcry from some animal rights activists, including in the House of Lords. Retrospective reviews of the serial have been generally positive, with reviewers praising the serial's atmosphere, although some have criticised its visual effects and lack of originality. Dicks novelised State of Decay twice in 1981, both for in print and for a talking book adaptation

Plot Still trapped in E-Space, the Doctor and Romana land on a planet whose only settlement is a medieval village under a high tower, from where the vampiric Three Who Rule regularly select villagers to be brought. The Doctor learns from villager Ivo that science is forbidden in the village. On their way out, they are ambushed by an band of rebels, led by scientist Kalmar. They show the Doctor ancient technology they have recovered detailing the crew of the Hydrax, a spaceship from Earth, and its crew, whom former guard Tarak recognizes as the Three Who Rule. Meanwhile, Adric, who has stowed away on the TARDIS, walks into the village and is sheltered by Ivo for the night.

On their way back, the Doctor and Romana are attacked by bats and led to the tower. There they meet lords Zargo and Camilla, who claim they protect the villagers. The Doctor protests that their society has backslid under their rule. Aukon, the last of the three lords, selects Adric from among the villagers and brings him a cave under the tower to become the first of the "chosen ones." Left alone, the Doctor and Romana find an inspection shaft and reach the flight deck of the Hydrax, where they discover fuel tanks filled with blood and hear a loud heartbeat. Aukon discovers them, leading the Doctor to realize the Three Who Rule are the original crew, not their descendants.

Tarak rescues the two, and leaves with Romana to rescue Adric, while the Doctor heads to the TARDIS. In the vampire crypt, Romana finds Adric in a trance. Zargo and Camilla awaken, killing Tarak and taking Romana prisoner as a sacrifice for the upcoming "arising." The Doctor lands in the rebel bunker and rouses them to attack the tower. Using a scanner, they discover a giant vampire creature under the tower.

The rebels attack the throne room. The Doctor finds the control for one of the Hydrax's scout ships and programs a flight path. In the cave below, Aukon calls on the giant vampire, the Great One, to arise and drink the blood of the sacrifice. The rebels evacuate as the scout ship takes off, waking Romana. As the claws of the Great One emerge from the ground, the scout ship turns back around and strikes the giant vampire through the heart, killing it. The Three Who Rule age rapidly and crumble into dust. The Doctor helps the rebels repair their computer and leaves to bring Adric home and find a way out of E-Space.

Production

Conception and writing

State of Decay originated in January 1977, when script editor Robert Holmes asked Terrance Dicks to write a storyline that would start off Doctor Who's upcoming fifteenth season. Both Holmes and Dicks had written Gothic-inspired serials for prior seasons, and Dicks revived a prior idea to write a Dracula-like vampire story in a science-fiction setting, which he originally titled The Witch Lords. Dicks was also simultaneously commissioned to write a novelization of the serial, to be released by Target Books. The original draft of the serial featured then-companion Leela, and saw the Doctor landing on a medieval-like planet ruled by vampiric nobles where the peasants roamed at night as zombies. Dicks submitted the script for the first episode of the serial, renamed The Vampire Mutations, on 25 January. Shortly after, BBC Head of Serials Graeme McDonald vetoed the storyline's production, fearing that the serial would be perceived as a spoof of the BBC's upcoming adaptation of Stoker's novel. Holmes commissioned Dicks to write Horror of Fang Rock as a replacement.

Dicks's script was revived in December 1979, when incoming producer John Nathan-Turner discovered that his predecessor Graham Williams had left behind almost no scripts that could be used for the series' eighteenth season. Knowing Dicks had written for the series before, Nathan-Turner first commissioned a revised outline to be due by the end of the month, followed by the scripts for the serial, to be due in February. While rewriting the scripts, Dicks came into conflict with Christopher H. Bidmead, the new script editor, who sought to place more emphasis on hard science and disapproved of Dicks's reworking of Dracula. Bidmead, disliking the Hammer horror-like tone of the first draft, encouraged Dicks to write the vampires as scientists and to focus the story more on the conflict between superstition and science, while Dicks wished to portray the vampires more in line with traditional horror clichés. Bidmead's influence led Dicks to devise the conceit of the vampires' castle originally being a crashed spaceship. The two both collaborated to add the element of the underground band of scientists to the script.

Bidmead also ordered Dicks to incorporate two new elements of continuity into the script, the new companion Adric and the storyline of the TARDIS being trapped in the smaller universe of E-Space. Dicks felt the concept of E-Space was never fully explained to him, and was equally unsure about how to involve Adric, having been given little direction and great liberty with writing him. Although the serial was initially planned to air second in the season, it was moved further up to allow for Adric's introduction. Bidmead vetoed the title The Vampire Mutation, feeling the audience should not know immediately that the villains were vampires. To Dicks's displeasure, Bidmead renamed the serial The Wasting, although this was changed to State of Decay during filming, as Dicks feared negative reviews making puns on the serial "wasting" viewers' time.

Dicks's scripts were approved on 12 March 1980. Despite this, Bidmead and Nathan-Turner requested rewrites to tone down the horror aspects of Dicks' scripts, and encouraged Dicks to incorporate scientific elements like a discussion of Grimm's law, which the writer felt slowed the story. Dicks, feeling that the character of K9 had been sidelined in previous stories, wrote a larger part for the character in Part Four. He included several in-jokes at Bidmead's expense, including the Doctor's comment comparing the TARDIS, which Bidmead wanted the show to use more actively, to a bus. More technological elements were introduced in further rewrites on 3 April. On April 11, McDonald demanded further rewrites of scenes he deemed too frightening, including the death of the vampires and several instances of violence.

Cast and crew Nathan-Turner approached Peter Moffatt, with whom he had worked on All Creatures Great and Small, about directing the serial, as the director was well known for his punctuality and careful planning that ensured shortened shoots. Moffatt accepted on 10 March based on Dicks's scripts, and was disappointed to find that Bidmead had encouraged him to tone down the horror elements. After he complained to Nathan-Turner, Moffatt was given permission to film an older version of the script with more of Dicks's stylistic elements intact, removing some of Bidmead's ideas, one of which was to have the vampires hatch from eggs. Amy Roberts, who had previously worked on Image of the Fendahl, was chosen as costume designer, alternating between serials with June Hudson. A former assistant, Norma Hill, was selected as make-up designer, while Tony Harding, who had worked on two previous serials as well as the BBC's Count Dracula, came on to design the visual effects. Christine Ruscoe, who had designed sets for Pyramids of Mars and The Hand of Fear, was chosen as the serial's set designer.

Matthew Waterhouse, an emerging actor who was a fan of the show, was cast as Adric by the end of March, having been recommended to Nathan-Turner by two sources. Although differing from the production team's idea of Adric, Waterhouse's audition impressed the team, who contracted him on 3 April for at least 20 episodes. Nathan-Turner took Waterhouse to lunch afterwards to assure that the actor was not a member of the Doctor Who Appreciation Society. Moffatt avoided Nathan-Turner's usual practice of casting big-name actors in guest roles, instead opting for character actors such as Arthur Hewlett as Kalmar. Moffatt chose to cast actors trained in theatre rather than television as the Three Who Rule to produce deliberately exaggerated performances and stylized vocality, which he described as "ham Shakespeare," eventually choosing Emrys James, Rachel Davies, and William Lindsay. He directed the three actors to move elegantly and ballet-like, to further the contrast with the naturalistic performances of the peasants. Welsh actor Clinton Greyn was cast as Ivo, while Rhoda Lewis was cast as Marta. Hewlett, James, and Greyn had all previously worked with Moffatt.

Design and effects