Written by William Emms. Planned as the fourth serial of Series 4, "The Imps" was a four-part story concerned about a spaceship overrun by Imp-like aliens and aggressive alien vegetation. The script was commissioned on 17 October 1966, and soon had to be rewritten to accommodate new companion Jamie. However, due to sickness on the part of Emms, this took so long that further rewrites were needed to explain the loss of Ben and Polly, its place in the schedule was taken by "The Underwater Menace" and on 4 January 1967 the story was dropped. Emms reused elements of the story in "Mission to Venus", a Choose Your Own Adventure-style story featuring the Sixth Doctor.