Skonnos was once the centre of a galactic empire and, although it has fallen into decay, it is still paid a regular tribute of seven youths from the planet Aneth. They are destined to be sacrificed to the Nimon, a bull-like alien who dwells within a vast power complex. In return, the Nimon has offered Soldeed, leader of the Skonnans, the ability to forge a new empire. When the Doctor and Romana find the ship carrying the Anethan tribute floating derelict in space, they are forced to help effect repairs. Romana is taken captive, while the Doctor discovers evidence that the Nimon's promises to Soldeed hide a far more terrible plan.

Every story televised as part of Doctor Who's seventeenth season was written by a writer who'd contributed to the programme before. But that wasn't what producer Graham Williams and script editor Douglas Adams had intended. In order to keep the show fresh, they had embarked on a strategy to recruit new writers to Doctor Who. Unfortunately, these plans gradually went awry as each of the resulting storylines eventually proved unusable; these included “Valley Of The Lost” by former producer Philip Hinchcliffe, “Erinella” by director Pennant Roberts, “Child Prodigy” by Alistair Beaton and Sarah Dunant, “The Doomsday Contract” by John Lloyd and Allan Prior, and “The Tearing Of The Veil” by Alan Drury. Indeed, Adams' frustration over this situation contributed to his decision to leave the script editor's post after a single season.

In early 1979, Adams' predecessor, Anthony Read, began discussing story ideas with the production team. He had previously collaborated with Williams on the Season Fifteen finale, The Invasion Of Time. Read had long been interested in the integration of Greek myths into science-fiction; in 1977, he had worked with Bob Baker and Dave Martin to adapt the legend of Jason and the Argonauts as Underworld. Read now turned his attention to the story of the Minotaur, a popular myth recounted in Ovid's Heroides and other sources. The Minotaur was a half-man, half-bull monster who was imprisoned in the Labyrinth designed by the architect Daedalus at Knossos in Crete. King Aegeus of Athens was compelled to offer seven Athenian boys and seven Athenian girls as tribute to King Minos of Crete, and they were sent into the Labyrinth to be slain by the Minotaur. Eventually, however, Aegeus' son Theseus volunteered to be part of the tribute, and he was able to slay the Minotaur with the help of Minos' daughter, Ariadne.

The legendary Labyrinth became the Power Complex and was envisaged as an enormous printed circuit

On March 23rd, Read was commissioned to write The Horns Of Nimon. He adapted many elements of the Greek legend such as the Labyrinth, which now became the Power Complex (originally known as the Complexity) and was envisaged as an enormous printed circuit. Many of the names in The Horns Of Nimon were corruptions of their mythological antecedents: the Minotaur became the Nimon, Theseus became Seth, Daedalus was reversed to become Soldeed, Athens became Aneth, Knossos became Skonnos, and the Greek city-state of Corinth became Crinoth. Sezom, by contrast, was a reference to the Biblical prophet Moses. The Skonnans were initially referred to as Skonnians.

Unfortunately, Williams quickly grew unhappy with The Horns Of Nimon, as he felt that the underlying ideas were not particularly strong. With no other scripts available, Williams was forced to proceed with Read's serial, but he decided to position it in the season's penultimate slot in the hope that it would quickly be forgotten once the finale, Shada, began transmission.

Williams also indicated that the scripts for The Horns Of Nimon should be amended to ensure that no film recording was required -- whether modelwork, on location, or in studio facilities. This cost-saving restriction had also been imposed on the preceding serial, Nightmare Of Eden. Both Destiny Of The Daleks and City Of Death had been expensive productions earlier in the year, and Williams was eager to save money for Shada. Fortunately, when planning his narrative, Read had been mindful of Doctor Who's meagre budget and the spiralling inflation of 1979. As a result, no major changes had to be made to the scripts. In the event, it was agreed that the model shot of the Power Complex's explosion could be captured on film, at the BBC Television Film Studios in Ealing, London.

The director assigned to The Horns Of Nimon was Kenny McBain, making his only Doctor Who serial. One of his key casting decisions was the central role of Soldeed, which went to Graham Crowden. In 1974, Crowden had been courted for the role of the Fourth Doctor before Tom Baker accepted the part. Lalla Ward continued to seek playful elements to incorporate into Romana's clothes. She worked with costume designer June Hudson on an outfit emphasised by a red riding coat, in reference to the colour which traditionally enraged bulls.

Graham Williams that he be succeeded as producer by production unit manager John Nathan-Turner

As The Horns Of Nimon neared production, decisions were being made about the future of Doctor Who. Having confirmed his intention to leave the show after Season Seventeen, Williams suggested that he be succeeded by production unit manager John Nathan-Turner, whom he had unsuccessfully attempted to promote to the post of associate producer at the start of the season. BBC Head of Serials Graeme MacDonald, on the other hand, was wary of putting a novice producer in charge of Doctor Who. Instead, he favoured former production unit manager George Gallaccio, who had recently produced the supernatural thriller The Omega Factor. Gallaccio, however, was keen to move away from science-fiction, and instead accepted the producer's post on the period drama Mackenzie. As a result, MacDonald consented to Nathan-Turner becoming the producer of Doctor Who from December.

Nonetheless, MacDonald remained concerned about Nathan-Turner's preparedness for such a demanding position -- especially since he himself was about to gain additional responsibilities as Head of a combined Series and Serials department. This meant that MacDonald would not be able to spend as much time supervising individual programmes like Doctor Who as he had in the past. Consequently, he turned to former Doctor Who producer Barry Letts who, since the spring, had been keeping an informal eye on his old show at MacDonald's behest. Letts now agreed to formalise this arrangement, and accepted an appointment as Doctor Who's first-ever executive producer for Season Eighteen. This assignment would receive retroactive approval in mid-June 1980.

Meanwhile, recording for The Horns Of Nimon was completed in two three-day blocks. The initial session was scheduled from September 24th to 26th at BBC Television Centre Studio 3 in White City, London. The first day involved work on the sets for Soldeed's laboratory, the Skonnan council chamber, and the entrance to the Power Complex. The other two days were devoted to material within the Power Complex itself: in the corridors and the Nimon's “larder” on the 25th, and in the central chamber on the 26th. Modelwork was also completed on the last day of the block.

Unfortunately, this studio session was plagued by overlooked gaffes. The police box exterior of the TARDIS still bore faint chalk marks from a September 21st photo session for a series of Denis Alan Print birthday cards, in which Tom Baker -- in costume as the Doctor -- had posed next to various numbers drawn on the TARDIS doors. With events being taped out of order, Soldeed's body was missing from the nuclear furnace area in several sequences. Malcolm Terris, playing the Co-Pilot, visibly split his trousers during his death scene. Most infamously, Crowden mistook the recording of Soldeed's demise for a camera rehearsal, and began laughing hysterically. With time pressing -- and despite the fact that McBain was already concerned that Crowden was overacting in the part -- the shot was retained.

On October 9th, part of the TARDIS set was erected incorrectly, with the roundels protruding outwards on one wall

The second studio session took place from October 7th to 9th in TC6. Time had run out on September 26th before all the model sequences could be recorded, and so these were the initial order of business. The remainder of the first day and much of the second then saw the completion of material aboard the Skonnan spaceship. Some of the Crinoth scenes -- namely those in the central chamber and at the transmat terminus -- were also taped on the 8th. Left for October 9th were the sequences in the “larder” and corridors on Crinoth, plus those in the TARDIS console room. Sadly, part of the TARDIS set was erected incorrectly, with the roundels protruding outwards on one wall.

In post-production it was found that the final installment of The Horns Of Nimon badly overran its twenty-five-minute timeslot. In the past, such a situation had typically been resolved either by repositioning the previous episode's cliffhanger, or else by reordering some scenes across the two installments. Indeed, Episode Three had proven to be unusually brief, even with the inclusion of a lengthy reprise from Episode Two. Nonetheless, it was found that all attempts to re-edit The Horns Of Nimon to meet its time constraints badly affected the serial's pacing. Consequently, on November 16th, authorisation was requested to air Episode Four in a half-hour timeslot.

Because it largely aired during the holiday season, the scheduling of The Horns Of Nimon was very inconsistent. On December 22nd, Episode One aired ten minutes later than usual, at 6.10pm, between the Basil Brush special Basil's Christmas In The Country and the variety show Christmas Snowtime Special. By contrast, Episode Two was scheduled ten minutes earlier than usual, at 5.50pm. For the first time in many years, Doctor Who followed on from Grandstand, with only an animated short and a news update intervening; it was now followed by Jim'll Fix It. For Episode Three, Doctor Who was pushed back to 6.20pm, and was preceded by Holiday On Ice, plus the news. Finally, on January 12th, 1980, the concluding episode of The Horns Of Nimon was back at the more typical time of 6.05pm. Its lead-in was the American superhero import Wonder Woman, as well as the news.

Williams' intention that The Horns Of Nimon be driven from viewers' memories by the spectacle of Shada did not work out as planned. Although the finale's production began as scheduled, it was subsequently disrupted by the latest round of industrial action at the BBC -- a situation which had already impacted the concluding serials of both Seasons Fifteen and Sixteen. As a result, Shada was abandoned, and The Horns Of Nimon brought Doctor Who's seventeenth season to an abrupt close. It therefore marked not only Anthony Read's final Doctor Who credit but, unexpectedly, that of Williams and Adams as well.

• Doctor Who Magazine #247, 15th January 1997, “Archive: The Horns Of Nimon” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #9, 22nd December 2004, “One Step Beyond” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #31, 2018, “Story 108: The Horns Of Nimon”, edited by Mark Wright, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Fourth Doctor by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.
• In·Vision #43, April 1993, “Production” edited by Justin Richards and Peter Anghelides, Cybermark Services.