In 1942, Walker succeeded Granville as principal "heavy" baritone, playing the Sergeant of Police in The Pirates of Penzance, Shadbolt, Don Alhambra, and Pooh-Bah. In succeeding years he added to these the Usher, Private Willis and Boatswain.
In 1942, Walker took over Granville's role as principal "heavy" baritone, performing roles such as Sergeant of Police in The Pirates of Penzance, Shadbolt, Don Alhambra, and Pooh-Bah.  Over the years, he expanded his repertoire to include Usher, Private Willis, and Boatswain.