Serial 4F:
Terror Of The Zygons


The Brigadier summons the Doctor back to Earth to investigate mysterious goings-on around Loch Ness in Scotland. The Doctor, Sarah Jane and Harry discover that the Loch Ness Monster is no myth -- in fact, it is really the Skarasen, a cybernetic reptile used as a servant by shape-shifting aliens known as the Zygons. The Zygons are paving the way for an invasion of Earth, and have already used their powers to infiltrate the local authorities.


As Robert Holmes settled fully into his role as Doctor Who's script editor and finished work on stories initiated by the outgoing production team, he began to cast about for new writers to commission for the programme. One candidate was an acquaintance of his named Robert Banks Stewart. Stewart had begun his career as a playwright before moving into television; amongst his many credits were The Avengers, Danger Man, The Saint and The Sweeney. Stewart had spent some time in Australia, where he had produced Intrigue. He had also been approached to contribute to Doctor Who during the programme's formative stages in 1963, though nothing had come of this.

A native of Scotland, Stewart was keen to set a Doctor Who adventure in his home country, and suggested to Holmes that the legendary Loch Ness Monster would make an ideal basis for a story, given that so few details existed about the nature of the mythical monster. Belief that some kind of creature -- possibly prehistoric in origin -- dwells in the loch may date back as much as 1500 years. It gained new popularity when a road passing by Loch Ness was constructed in 1933, with interest in the tale reaching a global scale in the 1960s. On March 12th, 1974, Holmes commissioned Stewart to prepare a six-part storyline under the title “Loch Ness”, with the request for scripts following on the 27th.

Robert Banks Stewart wrote the Doctor, Sarah and Harry in the vein of the protagonists of The Avengers

Stewart wrote his scripts over the remainder of the year. In the process, the length of the serial was curtailed from six installments to four. Unfamiliar with the style of Doctor Who, Stewart wrote the Doctor, Sarah and Harry in the vein of the protagonists of The Avengers, and had to be guided by Holmes in refining these elements.

Stewart originally placed a far greater emphasis on the Skarasen and the loch; the initial cliffhanger for episode two, for instance, involved the monster attacking the Doctor as he rows across Loch Ness, rather than traversing Tullock (originally Tulloch) Moor. Holmes felt that the Zygons were more interesting characters, however, especially since they could interact with the main cast, and asked Stewart to keep the focus of the serial firmly on them. As the scripts were rewritten, Sister White became Sister Lamont, the name of Stansgate House was changed to Stansbridge House, and Claymore Oil was rechristened Hibernian Oil.

During the early part of 1975, the adventure variously went by the titles “The Loch Ness Monster”, “The Secret Of The Loch”, “The Secret Of Loch Ness”, and “Secret Of Loch Ness”. By now, Serial 4F had been assigned to director Douglas Camfield, making his return to Doctor Who after a five-year absence. Camfield had last helmed Inferno, during which he had collapsed when the stress of production aggravated a heart murmur. He had been on a self-enforced sabbatical from the programme ever since, but was lured back by the concept of Stewart's story.

At the same time, several production decisions were being made which would have a significant effect on “Secret Of Loch Ness”. Throughout 1974, buzz had been building about Gerry and Sylvia Anderson's new science-fiction series Space: 1999, which was being developed for ITV, the commercial channel which was the BBC's principal rival. As 1975 dawned, it was apparent that Space: 1999 was set for a September debut. Since 1970, Doctor Who had been part of the BBC's winter programming slate, debuting in late December or early January. Concern now arose that if Doctor Who's thirteenth season started three months after Space: 1999 launched, viewing figures might be compromised.

Philip Hinchcliffe later admitted that Robert Holmes was right to believe that Harry was a valuable character

Consequently, in January it was decided that Season Thirteen would be brought forward to a late summer/early fall start, as had been the case throughout most of the Sixties. This meant that the thirteenth recording block, which normally wouldn't begin until September, would also have to start earlier. To facilitate this, Season Twelve was trimmed from twenty-six episodes to only twenty -- the shortest in Doctor Who history ot that point. “Secret Of Loch Ness”, scheduled to be the final serial of the twelfth recording block and originally intended to be the culmination of the twelfth season, would instead be held over to start Season Thirteen. Furthermore, the usual break between recording blocks would be eliminated entirely, with the twelfth and thirteenth blocks running together to essentially form one marathon production slate.

Meanwhile, Hinchcliffe also determined that Harry Sullivan should be written out of Doctor Who at the end of “Secret Of Loch Ness”. The character had been created at a time when it was thought that the Fourth Doctor might be played by an elderly actor who would be unable to participate in action sequences; with the casting of Tom Baker in the lead role, Hinchcliffe felt that Harry was now redundant. Holmes disagreed with the producer, believing that Harry was a valuable and distinctive ingredient of the series but nonetheless had Stewart amend his scripts appropriately; Hinchcliffe would later admit that Holmes' views had been correct.

The exit of Harry Sullivan also removed one more link between the series and the Earthbound UNIT format which had propelled it through the early Seventies. Hinchcliffe wanted to set more adventures on alien worlds, and actors Nicholas Courtney and John Levene, who had been contracted for “Secret Of Loch Ness” to once again play the Brigadier and Benton, became aware that their irregular appearances in Doctor Who might soon cease altogether. Meeting with Hinchcliffe in the BBC bar, Courtney suggested that the Brigadier should be killed off, exiting the series in a blaze of glory. Hinchcliffe turned down the idea, however, feeling that it would be an inappropriate fate for a character who had been so vital to the programme.

Nicholas Courtney suggested to Philip Hinchcliffe that Brigadier Lethbridge-Stewart should be killed off

Work on “Secret Of Loch Ness” began with location filming in West Sussex; sadly, the budget did not stretch to allow cast and crew to actually travel to Scotland. On the first day, March 17th, beach scenes were recorded at Climping Beach in Climping, while the arrival of the TARDIS took place on Ambersham Common in South Ambersham. Work continued on the Common the next day for sequences on Tullock Moor, while both the Zygon spaceship's landing area and the hospital exterior were actually Hall Aggregates Quarry, Storrington. The 19th was spent entirely at Ambersham Common, dealing with more material set both on the Moor and in the woods, as well the dematerialisation of the TARDIS.

On March 20th, the venue shifted to Charlton, with filming occurring at both the Fox Inn and a barn. The day after, Furnace Pond in Crabtree posed as Loch Ness. This should have marked the end of recording in West Sussex, but poor weather earlier in the week forced the allocation of two extra days. March 24th saw a return to Hall Aggregates Quarry for another hospital exterior shot, while the 25th was again spent at Ambersham Common, once more pressed into service as Tullock Moor. The same day, Elisabeth Sladen was contracted for twenty-two episodes of the thirteen recording block; Tom Baker's services had already been secured for all twenty-six episodes on the 21st.

On March 26th, footage of Millbank Tower in London was captured for use in the climactic Skarasen sequence. By now, both stop-motion animation and puppetry had been employed to bring the Skarasen to life. Unfortunately, this material proved to be of inferior quality, and Camfield decided to use as little of it as possible.

The first studio session then occurred in BBC Television Centre Studio 3. Monday, April 7th involved the taping of episode one, with the second episode following on Tuesday the 8th. Around this time, Hinchcliffe elected to change the serial's title, as he feared that emphasising the Loch Ness Monster was misrepresenting the story's contents. The adventure became “The Zygons” and finally Terror Of The Zygons. Recording shifted to slightly later in the week for the second studio block, which took place in TC4. Part three was completed on Tuesday, April 22nd, along with the lone Fargill Castle scene from part four. The remainder of the last installment was then taped on Wednesday the 23rd.

Ian Marter and Tom Baker wrote the screenplay for an unmade feature film called Doctor Who Meets Scratchman

The completion of Terror Of The Zygons brought Doctor Who's twelfth production block to a close, although work immediately proceeded onto the next set of episodes. This also meant that Ian Marter's time as a regular Doctor Who artiste had come to an end. Marter would continue to maintain a connection to Doctor Who, however: after returning for one more appearance as Harry shortly thereafter, in The Android Invasion, Marter went on to write several novelisations of Doctor Who stories for Target Books. He also authored an original Harry Sullivan novel, Harry Sullivan's War, for Target's short-lived The Companions Of Doctor Who range. He twice made unsuccessful bids to write for the TV series itself (once in 1980, and later with a submission entitled either “Strange Encounter” or “Volovox” for Season Twenty-Three), and with Tom Baker cowrote the screenplay for an unmade Doctor Who feature film called Doctor Who Meets Scratchman. Marter also continued to act on stage and television, earning credits on programmes such as Bergerac and The Return Of Sherlock Holmes. Unfortunately, Marter died of a diabetic condition on October 30th, 1986.

Inadvertently, Terror Of The Zygons also proved to be Nicholas Courtney's final Doctor Who appearance for many years, when scheduling issues prevented him from returning for The Android Invasion. Nonetheless, Courtney would eventually reprise the role of Lethbridge Stewart in the Eighties, in Mawdryn Undead, The Five Doctors, and Battlefield. Following the demise of the original Doctor Who series, Courtney played the Brigadier in the thirtieth-anniversary special Dimensions In Time, two radio plays starring Jon Pertwee as the Third Doctor (The Paradise Of Death and The Ghosts Of N-Space), and Death Comes To Time, the first original Doctor Who webcast. Courtney also lent his voice to several Doctor Who audio adventures from Big Finish Productions, including The Spectre Of Lanyon Moor, Minuet In Hell, Zagreus, Sympathy For The Devil, and installments of the UNIT series. He finally returned to play the Brigadier on television in 2008, in the Sarah Jane Adventures serial Enemy Of The Bane. Away from Doctor Who, Courtney continued to work prolifically, with his television appearances encompassing shows like All Creatures Great And Small, Yes, Prime Minister and The Bill. Courtney died on February 22nd, 2011 after a battle with cancer.

  • Doctor Who: The Handbook: The Fourth Doctor by David J Howe, Mark Stammers and Stephen James Walker (1992), Virgin Publishing, ISBN 0 426 20369 8.
  • Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing, ISBN 1 85227 444 1.
  • Doctor Who Magazine #210, 16th March 1994, “Archive: Terror Of The Zygons” by Andrew Pixley, Marvel Comics UK Ltd.
  • Doctor Who Magazine Special Edition #8, 1st September 2004, “You Ain't Seen Nothing Yet” by Andrew Pixley, Panini Publishing Ltd.
  • In-Vision #6, August 1988, “Production” edited by Justin Richards and Peter Anghelides, Cybermark Services.

Original Transmission
Episode 1
Date 30th Aug 1975
Time 5.46pm
Duration 21'41"
Viewers (more) 8.4m (29th)
· BBC1 8.4m
Appreciation 59%
Episode 2
Date 6th Sep 1975
Time 5.45pm
Duration 25'08"
Viewers (more) 6.1m (61st)
· BBC1 6.1m
Episode 3
Date 13th Sep 1975
Time 5.47pm
Duration 24'09"
Viewers (more) 8.2m (32nd)
· BBC1 8.2m
Appreciation 54%
Episode 4
Date 20th Sep 1975
Time 5.22pm
Duration 25'22"
Viewers (more) 7.2m (45th)
· BBC1 7.2m

Doctor Who
Tom Baker
Sarah Jane Smith
Elisabeth Sladen
Harry Sullivan
Ian Marter
Hugh Martin
Duke of Forgill
John Woodnutt
RSM Benton
John Levene
Tony Sibbald
Brigadier Lethbridge Stewart
Nicholas Courtney
Angus Lennie
The Caber
Robert Russell
Radio Operator
Bruce Wightman
Sister Lamont
Lillias Walker
Keith Ashley
Ronald Gough
Bernard G High
Peter Symonds

Written by
Robert Banks Stewart
Directed by
Douglas Camfield
Produced by
Philip Hinchcliffe

Production Unit Manager
George Gallaccio
Production Assistant
Edwina Craze
Title Music by
Ron Grainer &
BBC Radiophonic Workshop
Incidental Music by
Geoffrey Burgon
Special Sound
Dick Mills
Costume Designer
James Acheson
Sylvia James
Visual Effects Designer
John Horton
Studio Lighting
John Dixon
Studio Sound
Michael McCarthy
Film Cameraman
Peter Hall
Film Sound
John Tellick
Film Editor
Ian McKendrick
Script Editor
Robert Holmes
Nigel Curzon

Working Titles
Loch Ness
The Secret Of The Loch
[The] Secret Of Loch Ness
The Loch Ness Monster
The Zygons

Updated 1st July 2013