LLL. The Sea Devils

Season Nine - 1972

Script Editor: Terrance Dicks
Writer: Malcolm Hulke
Produced by: Barry Letts
Director: Michael Briant
Designer: Tony Snoaden
Incidental Music: Malcolm Clarke
Action: Havoc (6)
Extra Credit: The BBC wish to acknowledge the help given to them by the Royal Navy in the making of this programme


The Doctor and Jo visit the Master in his island prison. Besides visiting his old friend the Doctor is after assurance that the Master is secure - that he hasn't managed to use his hypnotism to escape. Colonel Trenchard gives the Doctor the impression that the guards are impervious to hypnotism.

Colonel Trenchard lets slip that ships have been disappearing, and the Doctor decides to have a look. After triangulating three of the disappearances the Doctor finds an abandoned base, and starts his investigations there - and Jo tags along. Whilst there they are attacked by Sea Devils, related to the Silurians.

The Doctor manages to escape and notifies the Navy, who want to launch an attack. The Master is involved, with Colonel Trenchard assisting. The Doctor stalls the Navy by offering to negotiate, but with the Master present this is difficult. The Doctor pretends to help the Master construct a machine that will enable the Sea Devils to emerge victorious, but instead sabotages it, and the Doctor and the Master escape as the Sea Devils' base is destroyed.

The Master fakes illness. He hypnotises, and disguises, one of the rescue crew, and manages to escape from the authorities.

Regular Cast

  • Jo Grant: Katy Manning

Guest Cast

  • The Master: Roger Delgado
  • Captain John Hart: Edwin Richfield
  • Third Officer Jane Blythe: Jane Murphy
  • Colonel George Trenchard: Clive Morton (1-4)
  • Sea Devil: Pat Gorman (1-2,4-6)
  • LDG Telegraphist Bowman: Alec Wallis (1,4-6)
  • Castle Guard Barclay: Terry Walsh (1-3 - uncredited for 2)
  • Alan Clark: Declan Mulholland (1-2)
  • Radio Operator: Neil Seiler (1)
  • Edwin Hickman: Hugh Futcher (1)
  • Robbins: Royston Tickner (1)
  • Castle Guard Wilson: Brian Justice (1)
  • CPO Smedley: Eric Mason (2)
  • Lieutenant Commander Tony Mitchell: David Griffin (3-5)
  • Commander Ridgeway: Donald Sumpter (3-5)
  • LDG Seaman Lovell: Christopher Wray (3-5)
  • Castle Guard Drew: Stanley McGeagh (2-4)
  • CPO Summers: Colin Bell (4-5)
  • Lieutenant Commander Watts: Brian Vaughn (4)
  • Chief Sea Devil: Peter Forbes-Robertson (5-6)
  • Walker: Martin Boddey (5-6)
  • A/B Girton: Rex Rowland (5)
  • Rear Admiral: Norman Atkyns (5)
  • CPO Myers: John Caeser (6)
  • Voice of DJ: Michael Briant (2)
  • Sea Devils: Steven Ismay, Brian Nolan, Frank Seton, Jeff Witherick
  • Chateau Guards: Stewart Barry, Bob Blaine, Les Clark, Jim Dowdall, Brian Gilmar, Phillip Weston
  • Ratings: Jim Dowdall, Nick Llewellyn, Roy Pearce, Dennis Plenty, Ron Tingley
  • Naval Base Sailors: Jim Dowdall, Brian Gilmar, Nick Llewellyn, Roy Pearce, Dennis Plenty, Ron Tingley, Phillip Weston; Stuntmen: Marc Boyle, Peter Brace, Alan Chuntz, Jack Cooper, Stuart Fell, Billy Horrigan, Mike Horsborough, Mike Stephens, Terry Walsh, Derek Ware

Original broadcast on the BBC

Channel Title Date Viewers Rating
BBC 1 312. Episode One Saturday, February 26, 1972 5:50 PM - 6:15 PM 6.4M
BBC 1 313. Episode Two Saturday, March 4, 1972 5:50 PM - 6:15 PM 9.7M
BBC 1 314. Episode Three Saturday, March 11, 1972 5:50 PM - 6:15 PM 8.3M
BBC 1 315. Episode Four Saturday, March 18, 1972 5:50 PM - 6:15 PM 7.8M
BBC 1 316. Episode Five Sunday, March 26, 1972 5:45 PM - 6:10 PM 8.3M
BBC 1 317. Episode Six Saturday, April 1, 1972 5:50 PM - 6:15 PM 8.5M

Click here to show repeat broadcasts on the BBC


  • Television Centre Studio 8

Outside Locations

  • HMS Reclaim; Norris Castle, Cowes, Isle of Wight
  • No Man's Land Sea Fort, Solent


Part 1: The Doctor has a telescope, which he uses to look at the Master's prison with. Yet when the camera switches to the close up of the castle, it shows the view from a pair of binoculars.

Part 1: When Jo and the Doctor are climbing the ladder to get into the sea-fort it's painfully obvious that it isn't Katy Manning, but a bloke in a Jo Grant wig.

Part 2: When the Doctor and Jo are carrying the fat guy out, you can see shadows and light moving around in the background as if there's someone there.

Part 3: When the submarine crashes to the sea bed there is a shot of the sub falling, cut to the inside and the crew fall around a bit. Then the sub hits the sea bed, in a model shot, then cut back again and they fall around a bit more.

The radio that the Doctor built couldn't have worked. If you look at the device (this is clearest right before it explodes), you can see that there's a 9 volt battery clip sticking out of it. The blooper is that there is no battery in the socket, so electricity cannot flow between the two metal terminals. Therefore the whole thing shouldn't be able to work at all because there isn't a complete circuit.


This was the last story that the Havoc team as a whole worked on.

Episodes One to Three exist in a converted NTSC format suitable for UK transmission.