The idea to equip battleships with heavy 152 mm secondary guns came about in 1909. The four Iron Duke-class battleships were similar to their predecessors but differed by more powerful secondary armament and larger dimensions. After commissioning in 1914, Iron Duke participated in World War I and was Admiral Jellicoes flagship during the Battle of Jutland. In 1919, she joined the Mediterranean Fleet and took part in the intervention in Soviet Russia. In 1939, she was transferred to Scapa Flow. On October 17, 1939, the ship was damaged by a German air raid and scuttled.