THE PROGRAMME: Having just defeated the Cybermen on Earth in The Invasion, The Doctor, Jamie and Zoe again plunge into the depths of Time and Space, emerging from the TARDIS onto the bleak terrain of an alien world... Although The Krotons formed part of Doctor Who's sixth series and made its debut at the end of 1968, the story's origins lay three series earlier in 1965 when, in the spring, writer Robert Holmes approached the production team with a possible narrative. Holmes' notion saw the Doctor and his three companions arrive on an uninhabited planet and become engulfed in a strange mist, which leaves them helpless against two robots who capture and take them inside a giant, ancient spaceship. Over the course of the four-part outline, the group would be rewarded for displays of intelligence, and encounter the humanoid controllers of the vessel from which they had to escape. The storyline as drafted in late April was not developed further since Holmes was informed that his robots were too similar to the Mechonoid robots which were about to feature in the serial The Chase. Holmes also became busy on other projects, and it was only when he found his outline during a house move in May 1968 that he resubmitted it to the current production team. This time, the idea was quickly taken up by incoming script editor Terrance Dicks, who with producer Peter Bryant commissioned a scene breakdown as Doctor Who and the Space-Trap (aka The Trap) in May, followed rapidly by a further commission for four scripts as Doctor Who and the Space Trap in June. The scripts were delivered by mid-August and provisionally planned for the end of the current run in spring 1969. Then, suddenly, The Space Trap was rushed into pre-production in early October 1968 when two other sets of scripts both hit problems. The surface of the desolate alien world inhabited by the Gonds was brought to life with location filming at two quarries in Malvern on Sunday 10 and Monday 11 November, followed by three days filming at Ealing Film Studios. Retitled The Krotons, the four episodes were then recorded at Lime Grove Studios on Fridays from 22 November to 13 December. As a cost-saving measure, there was no conventionally recorded music on the serial, but a series of 'tonal backgrounds' devised by Brian Hodgson of the BBC Radiophonic Workshop. The Krotons was released on VHS videotape by BBC Enterprises in February 1991, with sound effects and atmospheric tracks issued on two BBC CDs: Doctor Who at the Radiophonic Workshop and Doctor Who at the BBC Radiophonic Workshop: Volume 1 - The Early Years. With the situation on the distant planet resolved, the TARDIS trio headed to an Earth of the future, where Martian Ice Warriors were about to unleash The Seeds of Death... Programme notes compiled by Andrew Pixley.
