It is the year 1666, and the Great Plague runs rampant throughout England. In a small village, the Doctor, Adric, Nyssa and Tegan find the townsfolk behaving in an odd, hostile manner. Unemployed thespian Richard Mace tells them that a comet was recently sighted in these skies, and the Doctor suspects that it was actually a spaceship. Soon, the time travellers discover the presence of fugitive Terileptils, who are performing experiments on rats in the concealed basement of a manor house. The aliens have taken control of the villagers' minds, while their lethal android stalks the countryside dressed as the Grim Reaper.

When he became the script editor of Doctor Who at the early stages of its eighteenth season, one of Christopher H Bidmead's goals was to attract new writers to the programme. One name that was recommended to him was that of radio playwright Eric Saward. Although he had no prior television experience, Saward agreed to develop a proposal for Doctor Who. Around the end of March 1980, he submitted a story idea bearing the intentionally ludicrous title of “Invasion Of The Plague Men”. It was inspired by the work of former girlfriend Paula Woolsey, who had been studying the architecture which arose in the wake of the Great Fire of London in September 1666.

The conflagration, which raged for four days after starting at a bakery on Pudding Lane, had followed close on the heels of another catastrophe: the 1665 outbreak of bubonic plague. At the time, many believed that the so-called Great Plague had been portended by a bright comet observed in the skies over London at the end of 1664. Saward's girlfriend had observed that the black rats which spread the plague-carrying fleas became virtually extinct within months of the Great Fire. Saward thought that these elements would provide an effective science-fiction basis for a story about social conditions in mediaeval England. He also regarded “Invasion Of The Plague Men” as a vehicle to resurrect Richard Mace, a character he had created for several radio plays during the mid-Seventies. Originally an actor and detective living in Victorian London, Mace was now reimagined as a thespian put out of work by the closure of the theatres following the outbreak of plague.

John Nathan-Turner believed that Richard Mace's inclusion was the kind of whimsy he wanted to discourage

Unfortunately, “Invasion Of The Plague Men” did not find favour with producer John Nathan-Turner. He felt that Saward's narrative was too similar to 1977's The Talons Of Weng-Chiang. He also believed that the inclusion of Richard Mace verged on the kind of whimsy he wanted to discourage in Doctor Who. As a result, no progress was made on Saward's submission for several months, by which time Bidmead had turned his attention to Season Nineteen. It was now agreed that “Invasion Of The Plague Men” had enough potential to warrant giving Saward the opportunity to further develop his ideas. On September 17th, he was commissioned to provide a detailed storyline, with the title amended to “The Plague Rats”.

Several changes had to be made to Saward's original vision of the serial. It was now known that Tom Baker would be leaving Doctor Who at the end of Season Eighteen, and so Saward had to account for the presence of an as-yet-unknown Fifth Doctor. Romana and K·9 had been dropped from the companion line-up, and replaced by Adric and Tegan. Furthermore, Nathan-Turner was contemplating adding Nyssa -- a supporting character from Johnny Byrne's The Keeper Of Traken -- to the TARDIS crew as well. Saward was able to make the necessary amendments to his storyline and, on November 20th, he was commissioned to write the full scripts. The title was amended to the less-lurid The Visitation. Saward's aliens, the Terileptils, took their name from the phrase “territorial reptile”.

One milestone that Nathan-Turner asked Saward to incorporate into The Visitation was the destruction of the Doctor's sonic screwdriver. Nathan-Turner viewed the device -- which had featured in Doctor Who since Fury From The Deep in 1968 -- as an overly convenient plot contrivance, much like K·9. He thought that doing away with the sonic screwdriver would challenge Doctor Who's scriptwriters to be more imaginative in devising ways for the Doctor to solve problems, and would also make the Time Lord seem less invulnerable. After he was cast as the new Doctor in late 1980, Peter Davison came to share his producer's opinion. He felt that it would be more interesting if the Doctor instead carried an assortment of everyday objects in his pockets, which he could use in inventive ways to get out of trouble.

Meanwhile, Nathan-Turner was searching for a new script editor to replace Bidmead, who would be finishing his one-year contract at the end of December. Saward was encouraged to consider applying by Bidmead himself. Saward was interested, but he subsequently learned that the post was being filled by Antony Root; indeed, it was Root who helped shepherd The Visitation to its finished form. Unbeknownst to Saward, however, Root's appointment was only for three months on a trainee basis, after which he would be moving to a similar interim assignment on Juliet Bravo. While it was expected that Root would then come back to Doctor Who, he recommended that Saward be given the job for the intervening three months. Saward accepted the position in March 1981.

By the time Eric Saward joined the production team, Season 19 was undergoing a degree of upheaval

By the time Saward joined the production team in mid-April, Season Nineteen was already undergoing a degree of upheaval. The original premiere adventure, “Project Zeta-Sigma”, had been abandoned at a late date, forcing a rearrangement of the recording schedule. The Visitation was intended to air midway through Season Nineteen, but it was decided that it should be the second story into production, after Four To Doomsday. It would be directed by Peter Moffatt, whose last work had been on State Of Decay a year earlier.

Work on The Visitation began on May 1st, when material on Pudding Lane and in the bakery's oven room was recorded at the BBC Television Film Studios in Ealing, London. As the main Terileptil, Michael Melia wore a costume which incorporated remote-controlled animatronics for the alien's lips and gills. This was the first time such technology had been used in Doctor Who; it was conceived by visual effects designer Peter Wragg and constructed by Richard Gregory of the freelance firm Imagineering in Witney, Oxfordshire. Although the Terileptil costume was very expensive, Nathan-Turner was eager to combat the perception that Doctor Who monsters often looked like pantomime horses when they spoke.

Moffatt's team then travelled to Black Park in Fulmer, Buckinghamshire, where all of the scenes in the forest were shot between May 5th and 7th. Unfortunately, cast and crew found themselves filming below a Heathrow Airport flight path, and the noise of approaching aircraft regularly disrupted recording. Serendipitously, an air traffic controllers' strike put an end to these disturbances on the last day, and Moffatt was able to make up for the time he had previously lost. May 8th took the production to a manor house called the Tithe Barn in Hurley, Berkshire; it served as the exterior of the Squire's residence.

The rest of The Visitation was recorded at BBC Television Centre Studio 3 in White City, London. The initial recording block took place on May 20th and 21st. On the first day, Moffatt taped scenes in the stable and the Terileptil escape pod. The second day concentrated on the TARDIS sequences, along with those in the bakery and Mace's barn. The second session ran from June 3rd to 5th. These days were devoted to material in the manor house, although the opening TARDIS scene was remounted on the final day, after Nathan-Turner reacted negatively to the dialogue in the original version.

With The Visitation completed, there followed an almost two-month hiatus before work on Season Nineteen resumed. The break was scheduled to accommodate Davison's commitments to the second season of the sitcom Sink Or Swim, and marked the first time that such a lengthy pause had ever occurred in the midst of a Doctor Who production block.

The broadcast of The Visitation Episode One on February 15th, 1982 marked a change in the BBC's Monday evening line-up. The Rockford Files, which had been airing after Doctor Who, had completed its run the week before. It was now replaced by another James Garner-led American import: the Western sequel Bret Maverick.

• Doctor Who Magazine #275, 10th March 1999, “Archive: The Visitation” by Andrew Pixley, Panini UK Ltd.
• Doctor Who Magazine Special Edition #1, 2001, “Prince Charming” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #35, 2018, “Story 119: The Visitation”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Eighties by David J Howe, Mark Stammers and Stephen James Walker (1996), Virgin Publishing.
• Doctor Who: The Handbook: The Fifth Doctor by David J Howe and Stephen James Walker (1995), Virgin Publishing.
• In·Vision #58, June 1995, “Production” edited by Anthony Brown, Cybermark Services.