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PRODUCTION INFO

Name

The Sea Devils 2025

Serial Code

LLL

First Transmitted

7 December 2025

Final Ratings

TBA

DVD RELEASE

BLU-RAY RELEASE

GALLERY

The Sea Devils

CAST

Regular Cast

Jon Pertwee (Doctor Who) Katy Manning (Jo Grant)

Guest Cast

Roger Delgado (The Master), Edwin Richfield (Captain Hart), Clive Morton (Trenchard), Royston Tickner (Robbins), Neil Seiler (Radio Operator), Declan Mulholland (Clark), Hugh Futcher (Hickman), June Murphy (3rd officer Jane Blythe), Alec Wallis (Ldg. Telegraphist Bowman), Brian Justice (Castle Guard Wilson), Terry Walsh (Castle Guard Barclay), Pat Gorman (Sea Devil), Eric Mason (C.P.O. Smedley), Donald Sumpter (Commander Ridgeway), David Griffin (Lt. Commander Mitchell), Christopher Wray (Ldg. Seaman Lovell), Stanley McGeagh (Castle Guard Drew), Colin Bell (C.P.O. Summers), Brian Vaughan (Lt. Commander Watts), Rex Rowland (A/B Girton), Martin Boddey (Walker), Norman Atkyns (Rear Admiral), Peter Forbes-Robertson (Chief Sea Devil), John Caesar (C.P.O. Myers).

CREW

Written by	Malcolm Hulke
Directed by	Michael E. Briant
Produced by	Barry Letts

SYPNOSIS

The Doctor and Jo Grant visit theirold enemy The Master, who is the sole inmate of a top-security prison on a remote island off the south coast of England. Local shipping has been plagued by a series of tragic accidents and several ships have been lost. Joining forces with Captain Hart of the HMS Seaspite naval base, The Doctor learns that there have been garbled reports of sea monsters. Colonel Trenchard, Governor of the Master’s prison, believes that the ships are being attacked by enemy spies. The Master himself seems to be a reformed man and claims to have turned away from his life of crime.

Nothing could be further from the truth. The Master has in fact made contact with the Sea Devils, aquatic cousins of the prehistoric Silurian race encountered by The Doctor some time ago.

Having slept beneath the sea for millions of years, the Sea Devils have awoken and intend to reclaim what they consider to be their planet.

Aided and abetted by the evil Master, who will stop at nothing to take revenge on those who imprisoned him, the Sea Devils plan to eliminate the human race, a species they regard as nothing more than upstart apes

NOTES

Working titles for this story included The Sea Silurians.

Because of the story’s location filming requirements it was allocated the second slot in the production run for Doctor Who’s ninth season so as to allow filming in October. However to alternate the stories between those set on Earth and those set on other worlds it was transmitted third in the season. This was the first time stories were produced out of transmission order.

Re edited in 2025 for BBC Four transmission on 7 December 2025

The serial was mainly filmed around Portsmouth, Portsmouth HM Naval Base, No Man’s Land Fort, the Isle of Wight and HMS Reclaim.

The Royal Navy waived royalty fees on the use of stock footage and clips showing ships in action, happy with on-screen credited and the positive publicity generated by the show. Many sailors volunteered to help with the filming, so that most of the extras during the sequence at the Naval Base were actual service personnel, except in some of the stunts.

In the first episode, the script called for Jo Grant and The Doctor to climb up a ladder to get into a sea fortress. The ladder proved too slippery for Katy Manning, so stuntman Stuart Fell did the shot dressed as Grant.

A model of a submarine was created by purchasing a Woolworth’s submarine model kit and then altering the propeller. By chance, the alterations to the model strongly resembled an actual prototype submarine being developed by the Ministry of Defence.

The Doctor uses his sonic screwdriver to detect mines and cause them to explode.

Jo can operate a hovercraft.

After footage of the model was broadcast as part of the story, producer Barry Letts received a visit from two Ministry of Defence officials, who were concerned that the footage was of the prototype.

The Master was captured at Devil’s End. He is imprisoned at Fortress Island (The Daemons).