Lemuel Gulliver
Horsfall made several guest appearances in the BBC science fiction television series "Doctor Who". His first was as Lemuel Gulliver in "The Mind Robber" (1968). His other appearances were as a Time Lord in "The War Games" (1969), Taron in "Planet of the Daleks" (1973), and Chancellor Goth (intended to be the same character as he played in "The War Games") in "The Deadly Assassin" (1976). All four of these serials were directed by David Maloney. Many years later he returned to "Doctor Who", appearing in "Davros" – a "Doctor Who" audio drama produced by Big Finish Productions.