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 assumed Granville's position as the principal baritone with a heavy voice, taking on roles like Sergeant of Police in The Pirates of Penzance, Shadbolt, Don Alhambra, and Pooh-Bah.  He later added to his repertoire by performing as Usher, Private Willis, and Boatswain.