bernard kay had appeared in "the dalek invasion of earth" (1964). he would later appear in two more serials, "the faceless ones" (1967) and "colony in space" (1971). roger avon later played daxtar in "the daleks' master plan". tony caunter later played morgan in "colony in space" and jackson in "enlightenment" (1983). tutte lemkow previously played kuiju in "marco polo" (1964) and would appear again as cyclops in "the myth makers" (1965). gábor baraker had also appeared in "marco polo" (as wang-lo).