On the North Sea coast in the modern day, the Doctor, Jamie and Victoria learn of a series of mishaps and strange occurrences which has been plaguing the oil refineries. They soon find that a form of intelligent seaweed is rising up from the seabed, attempting to take over humanity -- and the invasion has already begun.

On September 24th, 1964, Doctor Who story editor David Whitaker rejected a proposal entitled “The Slide” from writer Victor Pemberton. However, Pemberton had also submitted a version of the same story idea, excluding Doctor Who elements, to BBC Radio, where it was accepted by script editor Peter Bryant and eventually broadcast during February and March 1966. “The Slide” concerned the efforts of a sentient form of mud to take over a small village.

In 1967, both Pemberton and Bryant found themselves working on Doctor Who. When Bryant, who was now the series' regular story editor, received a trial promotion to producer during the summer, Pemberton -- his assistant -- became the new story editor. Pemberton ultimately elected not to continue in the position past those initial three months, but did take the opportunity to suggest to Bryant that he write a new serial resurrecting elements of “The Slide”. Instead of mud, however, Pemberton took inspiration from the recent explosion of interest in natural gas and decided that the invading force should instead be sentient seaweed which thrived on the gas. This prompted a change in setting to a North Sea refinery.

“The Colony Of Devils” was commissioned by Bryant -- who had temporarily returned to his post as story editor -- on October 5th. Pemberton's adventure was targeted for production following The Enemy Of The World, as Serial QQ. However, towards the end of 1967, Bryant finally received a permanent appointment to the position of producer, to be replaced as story editor by Derrick Sherwin. Sherwin was less enamoured of Pemberton's scripts, and felt that several major changes needed to be made.

A subplot in episodes four and five was removed; this involved the Weed attacking a conference, as it could now traverse the entirety of Great Britain's network of natural gas pipelines. Victoria was to have killed Oak's partner (at this point named Swan) with her screams in part five, while Jamie was to have finally defeated the Weed at the story's climax by playing his bagpipes. Sherwin had Swan survive -- although he generally toned down the spookiness of the Oak and Swan double-act -- and used Victoria's amplified screams to kill the Weed instead.

To provide time for these rewrites, “The Colony Of Devils” was pushed back one spot in the recording schedule to become Serial RR, with The Web Of Fear brought forward to replace it. Pemberton was initially very unhappy about Sherwin's changes, and considered having his name taken off the scripts. Ultimately, however, Pemberton became satisfied with the story editor's decisions regarding what turned out to be his only televised Doctor Who serial (a subsequent idea, “The Eye In Space”, was rejected some months later; Pemberton additionally wrote the LP Doctor Who and The Pescatons for the Fourth Doctor and novelised both this and Serial RR).

Another major change had to be made when it became known that Deborah Watling would be leaving Doctor Who with “The Colony Of Devils”. Sherwin duly inserted material into the scripts to build up to Victoria's departure. As well, a few characters had to be renamed due to similarities with figures from other recent adventures. Swan became Quill (there having been a Swann in The Enemy Of The World), while the presence of a Corporal Blake in The Web Of Fear caused the change of Blake in “The Colony Of Devils” to Price. Less significantly, Lutyens was modified slightly to Van Lutyens. Meanwhile, at Pemberton's suggestion, the scene of the TARDIS landing was set at sea rather than on a cliff edge as originally scripted. This was done to avoid duplicating a similar materialisation at the end of The Rescue three years earlier.

The director assigned to “The Colony Of Devils” was Hugh David, who had handled The Highlanders the previous season. This was also his final Doctor Who serial. He went on to work on programmes like The Pallisers and The Man In The Iron Mask in addition to forming his own production company, Wildacre Productions. David died in the autumn of 1987.

Filming began with three days on location starting on February 4th, 1968. David and his team had hoped to obtain permission to shoot at a real refinery, but the Natural Gas Development Board denied this request. Instead, the Red Sands Sea Fort in the Thames Estuary served as the refinery platform. Filming also took place at Botony Bay near Kingsgate, Kent for scenes on the beach. At the suggestion of production assistant Michael Briant, the regular screwdriver which the script indicated the Doctor should use in one of these sequences was replaced by a “sonic screwdriver” (although the prop used was actually just a pen torch). This device would become a recurring favourite of the Doctor's.

Work then moved to the Ealing Television Film Studios, spanning February 7th to 9th. Most of the scenes recorded at this time were those which required use of the BBC's foam generator (Pemberton having envisaged the Weed as dwelling within a covering of foam). A fourth location day occurred on the 12th at the Denham Aerodrome in Denham, Buckinghamshire, when various helicopter close-ups were filmed. At about this time, the serial was retitled Fury From The Deep to avoid provoking controversy by using the word “Devil”.

The first five episodes of Fury From The Deep followed the usual Doctor Who production pattern and were taped on successive Saturdays in Lime Grove Studio D. Part one went before the cameras on February 24th. In addition, David's team returned to Ealing on March 5th and 6th to film the climactic battle against the Weed for episode six. Some of the material from part four was remounted alongside the recording of the fifth installment on March 23rd.

The next week saw taping shift to Studio 1 at the BBC's Television Centre. The antiquated confines of Lime Grove D had never been suitable for Doctor Who's complicated production, and the more modern Television Centre would be the programme's home for most of the rest of the fifth recording block. The change of scenery also meant that the taping of episode six was scheduled for a Friday, March 29th.

Although Victoria would reappear in the first part of the next story, The Wheel In Space (in material filmed as part of Fury From The Deep), this marked the end of Deborah Watling's regular involvement in Doctor Who. In addition to a considerable body of theatrical work, Watling thereafter appeared in television programmes such as The Newcomers and films including Take Me High and That'll Be The Day. She would later reprise her role as Victoria in the 1993 anniversary special Dimensions In Time and the video production Downtime. Watling also played Auntie in the Doctor Who audio drama Three's A Crowd from Big Finish Productions.

• 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 #277, 5th May 1999, “Archive: Fury From The Deep” by Andrew Pixley, Panini UK Ltd.
• Doctor Who Magazine Special Edition #4, 4th June 2003, “Heroes And Villains” by Andrew Pixley, Panini Publishing Ltd.