Ian Marter left university in 1969 and joined the Bristol Old Vic as an acting stage manager. In 1973 he was cast as John Andrews in a "Doctor Who" adventure. Jon Pertwee left the series during the following year, and the producers considered casting an older actor in the part. This meant that any physical action sequences might have to be performed by a younger actor (in the role of a companion to the Doctor) and Marter was thus cast as Harry Sullivan. When 40 year old Tom Baker landed the role of the Doctor, Marter became surplus to requirements and was written out shortly afterwards. Marter spent much of the rest of his life novelising "Doctor Who" adventures and films. He died suddenly and prematurely in 1986.