 Roles in which he occasionally deputised for Fancourt or Sydney Granville were King Hildebrand in "Princess Ida", the Pirate King in "The Pirates of Penzance", Earl Mountararat and Private Willis in "Iolanthe", Colonel Calverley in "Patience", Sir Roderic Murgatroyd in "Ruddigore", the title role and Pooh-Bah in "The Mikado", Wilfred Shadbolt in "The Yeomen of the Guard", and Don Alhambra in "The Gondoliers".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.