In August 1966, writer Geoffrey Orme submitted a script to the Doctor Who production office
entitled Under the Sea. The story was commissioned, but the production team soon realized that
this ambitious script would be difficult to produce on the standard Doctor Who budget.
Orme's story was dropped in favor of The Imps by Galaxy 4 writer William Eames. Unfortunately,
Eames fell ill and was unable to complete the script. So the production team elected
to reintroduce Orme's story, which was at this point known as The Fish People. The story
underwent a succession of hasty rewrites to reduce the cast numbers and also to introduce
new regular companion Jamie McCrimmon. But the late decision to continue with Orme's
scripts meant that the serial was late going into production. By the time location filming
began in December 1966, the serial had acquired its final title of The Underwater Menace.
Windspit Caverns in Dorset were used for the establishing shots of the volcanic island
and the sequences featuring the series regulars in the first and last episodes. The studio
sequences were filmed in Ealing Television Film Studios, utilizing the facility's water
tank for material involving the fish people, plus the drowning of Professor Zaroff. The
underwater swimming sequences featuring the fish people were achieved by having the artists
playing the creatures suspended by wires. The additional effects of back projection
and slow motion helped to create the illusion of being underwater.
Several of the cast members who featured in The Underwater Menace have notable links with
other Doctor Who stories. King Thousand Atlantis was played by Noel Johnson, who was better
known as the voice of Dick Barton in the famous radio serial Dick Barton's Special Agent.
He would later play Charles Grover, MP, in the John Pertwee story Invasion of the Dinosaurs.
High Priest Lolan, played by Peter Stevens, had appeared in the surreal William Hartner
story The Celestial Toymaker, where he had taken three roles as the knave of Harts, the
kitchen boy and the Billy Bunter type character Cyril.
Scientist Damon, played by Colin Jemans, returned to the world of Doctor Who in 1981 to play
George Tracy in T9 and Company.
Remaining on Earth, the TARDIS leaves the highlands of 18th century Scotland and arrives
on a small volcanic island sometime after 1968. The Doctor and his companions soon find
themselves in the lost city of Atlantis. But is Atlantis really the idyllic city of legend?