Analysis of information sources in references of the Wikipedia article "Robot (Doctor Who)" in English language version.
Eventually a suggestion by the wife of BBC drama head Bill Slater was followed up and the production team found the wild-eyed and naturally eccentric Tom Baker mixing cement on a building site.
Letts found casting a new Doctor more difficult, however, until a tip-off from his boss Bill Slater. An unemployed actor, then working on a building site, called Tom Baker had written to Slater asking for work. In, arguably, one of the best decisions ever made on Doctor Who, Letts cast Tom Baker as the fourth Doctor.
Having seen unknown hod-carrier Baker in The Golden Voyage of Sinbad, Letts took the goggle-eyed aspiring actor away from the building site and into the Tardis in 1974.
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