The TARDIS returns to Peladon fifty years after its first visit, and Queen Thalira, daughter of King Peladon, is now the head of state. The Galactic Federation desperately needs trisilicate -- in which Peladon is rich -- to wage a war against the oppressive Galaxy Five. But this has sparked dissension amongst Peladon's miners, inflamed by the manifestation of the ghost of Aggedor, the Sacred Beast of Peladon, to condemn the Federation. As Chancellor Ortron schemes for power, Alpha Centauri is convinced to summon help. When the Ice Warriors arrive, the Doctor is again suspicious of them; but is he repeating past mistakes?

Brian Hayles' The Curse Of Peladon, broadcast as part of Doctor Who's ninth season in early 1972, had proved popular with both the production team and audiences alike. When planning began for Season Eleven, producer Barry Letts and script editor Terrance Dicks agreed to approach Hayles regarding a sequel. Letts and Dicks would be preoccupied with their new science-fiction programme, Moonbase 3, and had decided to rely on established writers for Doctor Who that year. On January 4th, 1973, Hayles was commissioned to write a storyline under the title “Return To Peladon”. Letts asked Hayles to include a feminist element, while Dicks felt that the evocative culture of Peladon presented an opportunity for Doctor Who to delve into political intrigue.

Hayles originally approached “Return To Peladon” as a continuation of the previous adventure, taking place only slightly later in the reign of that serial's King Peladon. In this version of the story, Ortron and Eckersley were working together to make Peladon an independent world which would reap the profit from the demand for trisilicate. Thalira was one of the king's advisers; they had been due to marry, but she rejected him after he fell in love with Jo Grant in The Curse Of Peladon. Sarah's struggle to adjust to the alien cultures active on Peladon led her to become romantically involved with Eckersley.

Originally, Thalira was one of King Peladon's advisers, who was going to marry him prior to his affair with Jo Grant

Hayles' six scripts were commissioned on July 12th. Letts and Dicks soon grew concerned that “Return To Peladon” was becoming too complex, and Hayles worked with them to streamline the plot. In the process, the setting was shifted forward fifty years, with Thalira becoming the late King Peladon's heir. The title was amended to The Monster Of Peladon.

By late November, Dicks was still unhappy with Hayles' work. Given that the writer had now produced two radically different versions of the scripts, it was agreed that Hayles would be paid for his work and Dicks would complete the serial himself; this would be Hayles' final contribution to Doctor Who. The Monster Of Peladon consequently underwent numerous alterations; for instance, the Ice Warriors were originally defeated when the Doctor managed to transmit word of their treachery to the Federation, who blockaded and threatened to destroy the Ice Warrior planet. A casualty of the rewrites was a one-week delay to the serial's pre-filming at the BBC Television Film Studios in Ealing, London. This change of schedule meant that fewer facilities would be available to The Monster Of Peladon at Ealing, and one day would have to be shaved from the schedule.

Letts made a conscious effort to reassemble as much of the crew of The Curse Of Peladon as possible for The Monster Of Peladon. Most notably, Lennie Mayne returned as director, having also worked on The Three Doctors in the interim. Stuart Fell and Ysanne Churchman would again be Alpha Centauri's body and voice, respectively, while Nick Hobbs was hired to reprise his role as Aggedor. Various props, costumes and set elements from the earlier Peladon story were also reused, resulting in tight continuity between the two serials.

The Monster Of Peladon also saw the addition of a new member to the Doctor Who production team. The position of production unit manager had been newly created within the BBC to handle many of the financial aspects of a programme. The first production unit manager assigned to Doctor Who was George Gallaccio who, over the past year, had been a production assistant on Planet Of The Daleks and Invasion Of The Dinosaurs.

The abbreviated pre-filming for The Monster Of Peladon was the first recording for Doctor Who in 1974, taking place at Ealing from January 14th to 18th. Mayne's focus was on material in the tunnels and caverns of the Peladon mines. Jon Pertwee had been hampered by chronic back problems throughout the production block, and his condition had now become so acute that stuntman Terry Walsh filled in for him whenever any physicality was required. Unfortunately, this was particularly evident in the fight between the Doctor and Ettis at the end of Episode Four; Mayne was forced to try to distract the viewer by having Pertwee dub over some lines of dialogue. While recording the destruction of the sonic lance on the last day at Ealing, Ralph Watson -- who played Ettis -- was temporarily blinded when a magnesium flare accidentally ignited in his face.

Studio recording proceeded in the usual manner, with two-day sessions held every fortnight. The first two blocks took place on Mondays and Tuesdays, starting on January 28th and 29th at BBC Television Centre Studio 8 in White City, London. The Monday was dedicated to Episode One, with the establishing shot of the Citadel being the same one which had appeared in The Curse Of Peladon. Cast as Thalira's handmaiden was Mayne's wife, Frances Pidgeon. On the Tuesday, cast and crew concentrated on Episode Two, but also completed Episode Three scenes in the temple, the throne room and the pit. The second studio block, on February 11th (for Episode Three) and 12th (for Episode Four), was held in TC6. This was also the venue for the final session, although the recording days on this occasion were a Tuesday and a Wednesday: February 26th (for Episode Five) and 27th (for Episode Six).

• Doctor Who Magazine #216, 31st August 1994, “Archive: The Monster Of Peladon” by Andrew Pixley, Marvel Comics 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 #21, 2017, “Story 73: The Monster Of Peladon”, 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.