The 253rd episode of Doctor Who airs on the BBC. Jane Sherwin, David Savile and Philip Madoc guest star. The Time Lords make their earliest appearance in this story. This is Patrick Troughton’s final episode as the incumbent Doctor, the final Doctor Who episode of the 1960s, and the final episode made in black & white.
The following weekend, BBC1 gives Doctor Who’s Saturday evening time slot to the first British airing of an American science fiction series called Star Trek.