UNIT is called in when scientists begin disappearing from a top-secret research establishment. The Doctor discovers that they are being abducted into the past, and uses the TARDIS to follow them through time -- not realising that he has a stowaway aboard in the form of journalist Sarah Jane Smith. Arriving in the Middle Ages, the Doctor tracks the missing scientists to the castle of a warlord named Irongron. There he discovers that Irongron is in league with a Sontaran, Linx, who has crashlanded on Earth, and is now supplying the alien weaponry with which Irongron is terrorising the English countryside.

After writing Carnival Of Monsters at the end of 1971, Robert Holmes' next submission for Doctor Who came at the start of 1973. When “The Automata” was quickly rejected, Holmes met with producer Barry Letts and script editor Terrance Dicks, who instead proposed a story with an historical setting. In recent seasons, Doctor Who had only rarely ventured into the past, with 1972's The Time Monster a rare exception. Even on that occasion, the Doctor had travelled back into the mythic past with a visit to ancient Atlantis, rather than a recognisable historical era. Holmes was less than enthusiastic about this direction; he felt that historical serials were relics of Doctor Who's original educational mission. Nonetheless, he agreed to Dicks' suggestion of an adventure set in medieval times, provided that it would feature no historical personages and would include a strong science-fictional element.

On February 26th, Holmes was commissioned to provide a story breakdown under the title “The Time Fugitive”. One of the centrepoints of the narrative would be a new alien race called the Sontarans. Holmes had conceived of this martial species after reading On War, a ten-volume treatise on military strategy compiled in the early nineteenth century by the Prussian general Carl von Clausewitz. To offset his ennui with the actual business of writing a storyline, Holmes prepared his submission in the form of a military communique between the Sontarans “Hol Mes” and “Terran Cedicks”. Full scripts were requested on March 5th, by which time the adventure was known as “The Time Survivor”. It became The Time Warrior around mid-April.

The name of the Doctor's home planet was revealed to be Gallifrey in Episode Two

One significant change involved the story's climax: originally, it was the Doctor, rather than the archer Hal, who killed Linx by shooting an arrow into the Sontaran's probic vent. Also notable was Holmes' decision to provide a name for the Doctor's home planet for the first time. He initially referred to it as Galfrey, which was then refined to become Gallifrey, as revealed in the Doctor's Episode Two confrontation with Linx. The name Irongron came from the histories of Denmark. Early production documentation assigned the production code VVV to The Time Warrior, but it later became Serial UUU (with VVV ultimately going unused).

Meanwhile, Letts and Dicks were confronted with the challenge of devising a companion to replace the popular Jo Grant, whom Katy Manning had played for three years. A new character, referred to as “Smith”, was created during the early part of 1973. This role went to April Walker, an actress who had previously appeared in episodes of The Onedin Line, Dad's Army and Crossroads. She was contracted for Doctor Who's eleventh season on March 14th. When Jon Pertwee was presented with this news, however, he was unhappy that he had been offered no input into the casting process. He had worked with Walker before in the West End -- on Oh, Clarence! in 1968 -- and found that he had little chemistry with the actress. Walker also did not have the petite, slender body type that Pertwee felt worked best opposite his Doctor. As such, Walker's contract was cancelled on March 29th, although she would be paid in full.

It appears to have been at this stage that “Smith” was reimagined as journalist Sarah Jane Smith. Letts and Dicks intended that she be more independent and modern than Jo, in response to the accusations of sexism often levelled at Doctor Who. Because the production team had taken so long to develop Sarah Jane, her casting was a relatively belated affair. The last actress to be seen for the role was Elisabeth Sladen, who had originally assumed that she was merely being considered for a guest spot. After impressing Letts with her audition, Sladen was taken to meet Pertwee on April 13th, and quickly gained the star's approval as well. Sladen was contracted for Season Eleven on May 3rd.

As with the previous recording block -- which saw Carnival Of Monsters taped last, to be held over until the new year -- it was decided that The Time Warrior would be made at the end of the tenth block, but serve as the premiere story for Doctor Who's eleventh season. Letts originally hoped to direct the serial himself, but he and Dicks were busy gearing up for production on a new adult science-fiction series called Moonbase 3. Both men were now preparing to leave Doctor Who, and it was anticipated that they would be moved over to Moonbase 3 full-time, should its first season prove successful. Instead, veteran director Alan Bromly was offered The Time Warrior.

Location filming for The Time Warrior involved four days -- May 7th to 10th -- at Peckforton Castle in Peckforton, Cheshire. It served as both Irongron's castle and Wessex Castle, and its grounds offered areas suitable for the woodland scenes. Although medieval in appearance, Peckforton Castle actually dated from the mid-nineteenth century, when it was built for John Tollemache, the largest landowner in Cheshire. The appearance of the Sontaran, Linx, was a collaboration between costume designer James Acheson and make-up designer Sandra Exelby, who worked from Holmes' scripted description of a cross between a human and a toad. Actor Kevin Lindsay found the Linx costume very difficult to wear, as it interfered with his breathing.

The studio schedule for The Time Warrior followed the regular pattern for the production block, with recording taking place fortnightly on Mondays and Tuesdays. For the most part, Bromly dedicated each day to an individual episode. The first session took place on May 28th (for Episode One) and 29th (for Episode Two) at BBC Television Centre Studio 6 in White City, London. It was on the Tuesday that the strain of wearing both the Linx mask and the helmet became too much for Lindsay, who collapsed; Bromly's team subsequently learned that Lindsay suffered from a heart condition.

For the second studio block, on June 11th and 12th in TC1, Bromly arranged his shooting schedule to permit Lindsay as much rest as possible. In addition to shooting Episode Three on the Monday, Bromly also recorded the first few workshop scenes for Episode Four. The serial's concluding installment was then completed on the Tuesday; this was also the last day of Doctor Who's tenth production block. By now, some consideration had been given to retaining Hal the archer as a second companion, and Letts had approached actor Jeremy Bulloch to enquire about his schedule. Nothing would come of this, although Bulloch would go on to create the fan-favourite Boba Fett in The Empire Strikes Back, the 1980 sequel to Star Wars.

It was suggested that Robert Holmes might be suitable as Doctor Who's new script editor

On June 26th, Elisabeth Sladen was unveiled to the press. Meanwhile, with Dicks having made up his mind to leave Doctor Who after Season Eleven, it was agreed that a new script editor should be hired as soon as possible so that Dicks could be trailed throughout the next recording block. Occasional Doctor Who writer Louis Marks suggested that Holmes might be a suitable candidate. In spite of an uneasy meeting with Ronnie Marsh, the BBC's Head of Serials, Holmes won the job.

Over the summer, Letts asked Bernard Lodge of the BBC's Graphics Department to create a new title sequence to launch Doctor Who into its second decade. To date, Lodge had consistently used the “howl-around” technique for these assignments, but Letts now asked for something different. Lodge instead opted for slit-scan, in which abstract designs were photographed by a moving camera through an aperture cut in a solid mask, thereby creating an amorphous tunnel of light. The approach had been popularised by Douglas Trumbull for Stanley Kubrick's landmark 1968 film 2001: A Space Odyssey. Lodge also designed a diamond-shaped logo to replace the version used since the start of the Pertwee era. Both the new title sequence and the new logo would make their debut with The Time Warrior.

Another significant change in post-production was the loss of Hal's introductory scene from Episode One. It featured the archer flirting with a serving girl named Mary, and explained that he had accompanied Sir Edward on one of the Crusades, helping him return home after falling sick in the Holy Land. The loss of this sequence resulted in the omission of all of Mary's dialogue from the finished serial and, as a result, actress Jacqueline Stanbury would no longer be listed in the credits.

Following the conclusion of The Green Death at the end of Season Ten, Doctor Who's timeslot was largely filled by silent movies during the summer, and then the quiz show Who, What Or Where? in the autumn. It was originally thought that Season Eleven would begin on December 29th, which would have been in keeping with recent years. Subsequently, however, it was decided to bring the premiere of The Time Warrior forward by two weeks, to December 15th, to help propel viewing into the Christmas period.

As a result, the scheduling of The Time Warrior was highly variable. Episode One aired at 5.10pm, after Grandstand and before a news update and The Wonderful World Of Disney. Episode Two aired at 5.50pm, after The Movie Quiz and the news, and before Bruce Forsyth And The Generation Game; Doctor Who would be regularly paired with the latter during the early part of the season. Episode Three moved back to 5.10pm, but this time it was separated from Grandstand by the news and weather, and was followed by a sports summary prior to the Forsyth show. It wasn't until Episode Four aired on January 5th, 1974 that Doctor Who settled into its new regular timeslot, at 5.30pm -- twenty minutes earlier than the year before. Its full lead-in would now be Grandstand, a Walt Disney cartoon short and finally the news update, while Bruce Forsyth And The Generation Game now aired immediately afterward.

• Doctor Who: Invasion Of The Dinosaurs DVD Production Subtitles by David Brunt (2012), 2|entertain.
• Doctor Who Magazine #246, 18th December 1996, “Archive: The Time Warrior” by Andrew Pixley, Panini UK Ltd.
• Doctor Who Magazine Special Edition #2, 5th September 2002, “The Show Must Go On” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #20, 2016, “Story 70: The Time Warrior”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Third Doctor by David J Howe and Stephen James Walker (1996), Virgin Publishing.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.