The Earth is on the brink of a new Ice Age. The TARDIS arrives at Brittanicus Base in England, where a small team of scientists desperately tries to hold back the glaciers. But even as their equipment starts to fail, Leader Clent's faith in the infallibility of the Base computer's instructions remains unshakable. Meanwhile, a Brittanicus team has unearthed a reptilian figure from the glacier, which they dub an Ice Warrior. But the Ice Warrior soon revives, and reveals himself to be a Martian named Varga, whose spaceship crashlanded on Earth long ago. Varga sets out to free his dormant crew from the glacier -- no matter the cost.

By the spring of 1967, monsters had taken on a new importance to Doctor Who. The change of emphasis wrought by producer Innes Lloyd over the past year -- first in concert with story editor Gerry Davis, and then with his successor, Peter Bryant -- had seen the programme move towards more populist science-fiction fare. This typically meant confronting the Doctor and his friends with a steady diet of menacing creatures, and the production team wanted to develop some regular monsters that would seize the public's imagination. The usage of the Daleks would be limited for the foreseeable future, due to the efforts of their creator, Terry Nation, to market them in the United States. The recently-introduced Cybermen would only partially make up for their loss. As such, Lloyd and Bryant approached Brian Hayles -- who had last written The Smugglers a year earlier -- to develop a new Doctor Who monster with the potential for repeat appearances.

Hayles found inspiration in an article he had recently read about the discovery of the well-preserved corpse of a wooly mammoth, which was excavated from the Siberian ice in 1901. He was also intrigued by the planet Mars, and wondered what some of race could conceivably have flourished in its environment. These notions led him to imagine a scenario in which a Martian was discovered on Earth, frozen in a glacier, and then brought back to life. With this as his starting point, Hayles was commissioned to write The Ice Warriors on July 21st.

Victor Pemberton was replaced as assistant story editor by Derrick Sherwin

For some time in mid-summer, it was unclear whether Hayles' story or Mervyn Haisman and Henry Lincoln's The Abominable Snowmen would be the first into production as part of Doctor Who's fifth recording block. Eventually, however, the other serial's requirements for location filming dictated that The Ice Warriors would be made second. No fewer than three story editors worked on Hayles' scripts. In addition to Bryant himself, Victor Pemberton had a three-month posting as story editor while Bryant enjoyed a trial promotion to producer. Then, when Pemberton left the production office around the end of the summer, he was replaced as Bryant's assistant by Derrick Sherwin. With Lloyd intending to leave Doctor Who later in the year, the plan was now for Bryant to replace him on an ongoing basis, with Sherwin as the new story editor.

Hayles envisaged the Ice Warriors as Viking-like cybernetic creatures, with high-tech instruments built into their armour and helmets. Costume designer Martin Baugh, however, saw the creatures as more reptilian, with armour and helmet integrated into their carapace. This approach met with the approval of Derek Martinus, the story's director; he had most recently handled The Evil Of The Daleks towards the end of the previous production block.

Filming for The Ice Warriors began at the BBC Television Film Studios in Ealing, London on September 25th. The focus was largely on scenes set within the glacier and in the wilderness outside Brittanicus Base. Work there continued through to September 29th, and then concluded after the weekend, on October 2nd. On September 27th, Patrick Troughton was issued a new contract, which included The Ice Warriors and three additional six-part serials. Deborah Watling also received a contract extension, securing her services for both the present story and The Enemy Of The World, which would be next into production.

As usual, recording took place on consecutive Saturdays at Lime Grove Studio D in Shepherd's Bush, London. Episode One was scheduled for October 21st. Clent's limp and use of a cane were not scripted, but had been developed during rehearsals by actor Peter Barkworth; a further suggestion of a stammer was vetoed by Martinus. Meanwhile, although he generally happy with Baugh's Ice Warrior costumes, Martinus had deemed some modifications to be necessary following the work at Ealing. Most notably, the original helmets had proved to be very restrictive, and a slimmer, more flexible design was requested -- even though this would create a visual discrepancy between those scenes which had been completed on film and those which would be taped in the studio. The costume for Varga was prioritised for refurbishment, and this was completed in time for the recording of Episode Two on October 28th. The same day, a special trailer was taped for The Ice Warriors, featuring Barkworth as Clent and Peter Sallis as Penley. It was broadcast after the concluding installment of The Abominable Snowmen on November 4th.

By Episode 3, all of the Ice Warriors costumes had been redesigned to varying degrees

November 4th was also the day that Episode Three was taped and, by now, the other Ice Warrior costumes had also been redesigned to varying degrees. Three weeks later, on November 25th, the final installment of The Ice Warriors was recorded. Unfortunately, Watling was not available that evening, and so the scenes for which her character was essential had to be recorded during the afternoon. For the remainder of the episode, the scripts were rewritten to have the Doctor send an unseen Victoria back to the TARDIS; she was originally supposed to return to Brittanicus Base with him, and would have appeared in the final control room sequence.

Part one of The Ice Warriors aired fifteen minutes earlier than usual, at 5.10pm, to accommodate the British Legion Festival of Remembrance, which was broadcast later the same day. This meant that Doctor Who was scheduled directly after Grandstand, without the intervening Tom And Jerry cartoon short which preceded the serial's other five installments.

• Doctor Who Magazine #303, 2nd May 2001, “Archive: The Ice Warriors” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Heroes And Villains” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #11, 2016, “Story 39: The Ice Warriors”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing.