She was refitting at Portsmouth from 18 April-22 June 1916 and missed the Battle of Jutland on 31 May, the most significant fleet engagement of the war. "Dreadnought" became flagship of the 3rd Battle Squadron on 9 July, based at Sheerness on the Thames, part of a force of pre-dreadnoughts intended to counter the threat of shore bombardment by German battlecruisers. During this time, she fired her AA guns at German aircraft that passed over her headed for London. She returned to the Grand Fleet in March 1918, resuming her role as flagship of the 4th Battle Squadron, but was paid off on 7 August 1918 at Rosyth. She was recommissioned on 25 February 1919 as the tender "Hercules" to act as a parent ship for the Reserve.