18 February 1989: death of John Bailey, who played the Commander in The Sensorites (1964), Edward Waterfield in The Evil of the Daleks (1967), and Sezom in The Horns of Nimon (1979-80).
18 February 1993: death of Jacqueline Hill, who played the First Doctor's companion Barbara Wright (and actually says the first audible line in the very first episode) from 1963-65, and returned in 1980 to play Lexa in Meglos.
ii) broadcast anniversaries
18 February 1967: broadcast of second episode of The Moonbase. The Doctor works out that the Cybermen have been poisoning the sugar.
18 February 1978: broadcast of third episode of The Invasion of Time. The Vardans take over; Leela and Rodan contact the Shobogans; Andred threatens to kill the Doctor.