The Doctor is delighted when the TARDIS lands near a monastery in Tibet because it means he can return the monks' sacred ghanta which he took with him for safekeeping centuries earlier. But all is not well at the monastery: there is disharmony amongst the monks, and the countryside is overrun by robotic Yeti. Soon, the Doctor finds himself accused of murder, whilst an extradimensional force called the Great Intelligence prepares to return to Earth... using one of the Doctor's friends as a vessel.

Both Mervyn Haisman and Henry Lincoln had gotten their start in the entertainment business as actors (Lincoln using the stage name “Henry Soskin”). They met on Emergency Ward 10, for which Haisman contributed scripts and Lincoln performed; Lincoln had few authorial credits to his name at this point, while Haisman had also written for Doctor Finlay's Casebook and No Hiding Place. In early 1967, Lincoln encountered his friend, Patrick Troughton, who complained about the lack of Earth-based stories during his first season on Doctor Who.

Lincoln seized on the idea of basing an adventure around the Yeti, monsters which legend held lived in the upper reaches of the Himalayan mountains. Word of the Yeti began spreading in 1887 and the story became popularised throughout the first half of the twentieth century, during which time the conflation of the phrases “abominable snow” and “man of the mountains”, contained in a wire report, gave rise to the nickname “the Abominable Snowman”. Haisman and Lincoln approached the Doctor Who production office with their idea, and were commissioned to write The Abominable Snowmen on May 2nd.

This was the first serial instigated by new story editor Peter Bryant, shortly after taking over from the departed Gerry Davis. When Bryant was given a three-month test period as producer over the summer, his replacement, Victor Pemberton, also carried out some work on the scripts. Keen to capture the Tibetan culture accurately, Haisman and Lincoln used authentic names and details for the Detsen monastery, including the tongue-twisting Padmasambhava, an historical Buddhist master. Innes Lloyd -- who returned to the job of producer following Bryant's trial run -- was very pleased with The Abominable Snowmen and saw it as a great opportunity to introduce more location work into Doctor Who. As a result, many of the sequences which the writers had envisioned as being carried out in the studio would in fact be designated for location filming.

For a time, there was some uncertainty as to whether The Abominable Snowmen or The Ice Warriors would be the first story made as part of Doctor Who's fifth production block (The Tomb Of The Cybermen, made at the end of the fourth block, was being held over to start the new season). By July 22nd, however, Haisman and Lincoln's serial had gotten the nod, at least in part because the location work would be more easily accomplished during the summer. The director assigned to The Abominable Snowmen was Gerald Blake, who had worked on series including Z Cars and Doctor Finlay's Casebook. In early 1964, Blake had been scheduled to helm an unmade historical Doctor Who adventure set at the time of the Spanish Armada, written by then-story editor David Whitaker.

On July 28th, the services of the Doctor's companions were secured for The Abominable Snowmen when both Frazer Hines and Deborah Watling were issued new contracts; Hines' also covered The Ice Warriors. Subsequently, Watling suggested to Lloyd that her father, respected actor Jack Watling, might be suitable for the role of Professor Travers. This jibed with Lloyd's own thoughts on the part, and the senior Watling was duly cast. Jack Watling had starred in television series such as The Power Game and The Plane Makers, as well as feature films including A Night To Remember.

Work on The Abominable Snowmen, designated Serial NN, began on August 23rd at the Ealing Television Film Studios, where the scenes in the Yeti cave were filmed. Also recorded at this time was a shot of Padmasambhava's wizened head melting, which was due to be incorporated into part six. This was considered too horrific, though, and went unused.

Cast and crew then embarked on what was, at that point, the longest location shoot ever allocated to Doctor Who. It covered six consecutive days, beginning on September 4th, and took place at Nant Ffracon Pass and Ogwen Lake in the Snowdonia Mountains at Gwynedd, Wales. Unfortunately, a lack of snow -- compounded by several days of rain, making the ground muddy and slippery -- meant that the footage failed to convey the wintry setting suggested in the script. The rain also caused trouble for the actors, particularly those in the Yeti costumes, who found themselves falling frequently.

Throughout the second half of Season Four, Doctor Who had been taped only a week ahead of transmission, a perilous situation which Lloyd was not keen to repeat. It was therefore decided to record episodes one and two of The Abominable Snowmen on consecutive days -- Friday, September 15th and Saturday, September 16th. This would provide a three-week cushion between production and transmission; the remaining four installments would then be taped, as usual, on successive Saturdays beginning on the 23rd and concluding on October 14th. The venue was Doctor Who's regular studio home of Lime Grove D.

The Yeti were a big hit with Lloyd and Bryant, who saw in them the potential for another popular success. This had become particularly important in recent months, as Dalek creator Terry Nation's efforts in Hollywood to develop a series based around the pepperpots meant that Doctor Who had lost -- for the time being, at least -- its most potent villains. Consequently, three days before The Abominable Snowmen part four went before the studio cameras, Lincoln and Haisman were commissioned to write a sequel, entitled The Web Of Fear. A rematch between the Doctor and the Yeti was therefore only weeks away.

• Doctor Who: The Handbook: The Second Doctor by David J Howe, Mark Stammers and Stephen James Walker (1997), Virgin Publishing, ISBN 0 426 20516 2.
• Doctor Who: The Sixties by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing, ISBN 1 85227 420 4.
• Doctor Who Magazine #224, 12th April 1995, “Archive: The Abominable Snowmen” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Heroes And Villains” by Andrew Pixley, Panini Publishing Ltd.