Serial 5E:
The Power Of Kroll

Working Titles: Moon Of Death, Horror Of The Swamp, The Shield Of Time.
Starring: Tom Baker (The Fourth Doctor), Mary Tamm (The First Romana).

For the fifth segment of the Key to Time, the Doctor and Romana travel to the marsh moon of Delta Magna. There, the time travellers become enmeshed in tensions between the barbaric native Swampies, the gun-runner Ro
hm-Dutt, and the crew of a refinery which is trying to drive the Swampies away. In the midst of all this, the Swampie god, a gargantuan squid named Kroll, is beginning to stir, and even the Doctor will be defenseless in the wake of the destruction Kroll will wreak.

When the originally planne
d fourth story for Season Sixteen, written by Ted Lewis, was abandoned in February 1978, script editor Anthony Read turned to Robert Holmes, whom he had replaced in the post. Holmes had written a number of Doctor Who serials, most recently the season opener, The Ribos Operation. Consequently, he was familiar with the Key To Time storyline which was running through all the stories that year, and agreed to rapidly produce a new four-part adventure. Read requested that he include "the biggest monster ever" in Doctor Who history. Holmes was unhappy with this suggestion, fearing that such a creature would be difficult to pull off on Doctor Who's limited budget, but agreed to the stipulation nonetheless. Moon Of Death was commissioned on May 26th.

The title was soon altered to Horror Of
The Swamp, and then to The Shield Of Time. This latter change came about because of a short-lived idea to further tie the Season Sixteen stories together by giving them all names of the form The (Something) Of Time. When this concept was abandoned, the title was changed again to The Power Of Kroll. Meanwhile, the director originally assigned to the story, Michael Hayes, grew increasingly concerned about the serial's technical demands. As a result, producer Graham Williams decided to shift The Power Of Kroll back to fifth in the running order, moving up The Androids Of Tara to take its place. The story's new director was Norman Stewart, who had helmed the similarly-complex Underworld the year before.

Several cast changes o
ccurred prior to the commencing of production on Serial 5E. Film star George Baker was originally pursued to portray the main villain, Thawn. When Baker proved unavailable, both Philip Madoc (who had been in several Doctor Who serials, most notably The Brain Of Morbius where he played Mehendri Solon) and Neil McCarthy were considered for the part. McCarthy won the role, but when Alan Browning, who was to play Fenner, became too ill to take part, Madoc was contacted about replacing him. In the meantime, Madoc had forgotten which role was which and believed he was still being asked to play the story's main villain. He was very disappointed to discover he was instead cast in a supporting role, and this would transpire to be his final Doctor Who appearance. Meanwhile, Martin Jarvis was asked to portray Dugeen, which ultimately did not come to pass. As a cost saving move, it was decided to replace him with K-9 voice actor John Leeson. Leeson was contracted for the entire season, but K-9 was omitted from The Power Of Kroll because he was a poor fit in the serial's marshy setting.

on filming began on September 18th around the river Alde in Suffolk. The next day was the first time the Swampies appeared in make-up, using a German product selected by make-up artist Kezia Dewinne for its striking appearance on camera and its insolubility in water -- a valuable characteristic, given the serial's damp locales. Unfortunately, Dewinne neglected to also order the special solvent needed to remove the make-up. In the end, the cast and crew had to travel to a nearby American air force base where industrial-strength solvents were applied; nonetheless, many of the Swampie actors would have green-tinged skin for weeks afterward.

Further problems occurre
d when film cameraman Martin Pathmore acted on poor advice by attempting to achieve the merger of location material and model Kroll material using a hard matte fitted on the camera lens. This meant that a solid line was still visible in the frame where the two different sources were combined, making the scenes look very fake. Then, during model filming on October 19th and 20th, visual effects designer Tony Harding discovered that his model for the refinery could not be photographed from the correct angle due to problems with the tank facilities.

A single three-day studio session was allocated to The Po
wer Of Kroll, beginning on Monday, October 9th. Around this time, Williams fell badly ill and could not continue working on the serial. Production unit manager John Nathan-Turner assumed the producer duties on the remainder of The Power Of Kroll, while David Maloney -- a director on numerous Doctor Who stories, most recently The Talons Of Weng-Chiang two years earlier -- took over pre-production on the season's final serial, The Armageddon Factor. It was also around this time that Mary Tamm reaffirmed to the production crew that she would not be returning to Doctor Who for Season Seventeen. Tamm had always intended to remain on the show for just one year, and the tribulations of The Power Of Kroll only served to reinforce her convictions.