Trivia: At the end of episode 3 of "The Deadly Assassin", Doctor Who is attacked and has his head held underwater for a very long time. The "cliffhanger" ending of episode 3 is a freeze frame shot of Doctor Who (Tom Baker) under the water, apparently drowned. This ending elicited much criticism from Mary Whitehouse and the vocal National Viewers and Listeners Association, who lobbied to have Doctor Who taken off the air, or at least moved to a post-"9pm watershed" slot. In an interview in 1994, Whitehouse said that the ending of this episode still disturbed her, more than 14 years later.
Trivia: "The Deadly Assasin" was the ONLY Doctor Who story in which the Doctor does not have a "companion" of some kind. The previous companion, Sarah Jane Smith (played by Elizabeth Sladen) was 'written out' in the previous story "The Hand of Fear", and the next companion, Leela (Louise Jameson) did not come on board the TARDIS until the next story "The Face of Evil"