Bill Slater became Head of Serials at the British Broadcasting Corporation during production of season 11. He was thus involved in the search for the Fourth Doctor. Since Slater had previously directed Baker in a Play of the Month called The Millionairess, Baker famously wrote to Slater on 5 February 1973 looking for work. The letter arrived just when Slater was looking for a person to recommend to Barry Letts and Terrance Dicks, the people who were effectively in charge of the casting. Conveniently, Baker was then appearing in The Golden Voyage of Sinbad, which was playing in a cinema proximate to BBC Television Centre. Slater recommended that Letts and Dicks go there to see if they thought, like him, that Baker would make an ideal Doctor. Liking what they saw, they cast Baker shortly thereafter.
- Internet Movie Database at the