Following the outbreak of World War I, the squadron was attached to the Channel Fleet before "London" was detached in March 1915 to participate in the Dardanelles Campaign, supporting ANZAC forces as they landed at Gaba Tepe and Anzac Cove on 25 April 1915. She remained in the Mediterranean, supporting the Italian Royal Navy in the Adriatic Sea until October 1916. Returning to the United Kingdom, she was inactive until being converted to a minelayer in early 1918, which entailed the removal of her main armament. She served with the Grand Fleet's 1st Minelaying Squadron until the end of the war. Placed in reserve in 1919, she was eventually broken up for scrap in 1920.