Work on all four ships was suspended at the beginning of the First World War and the two ships to be built in the Royal dockyards were cancelled on 26 August 1914, as it was believed that they could not be completed before the end of the war. Admiral Lord Fisher, once he returned to office as First Sea Lord in October, began pressuring Winston Churchill, then First Lord of the Admiralty, to allow him to convert the suspended contracts for "Renown" and "Repulse" into a new class of battlecruisers capable of the very high speed of . Churchill argued that their construction would interfere with other construction programmes, absorb too many resources, and still could not be finished in time. Fisher countered by arguing he could keep the building time to a minimum, as he had done with , by using as much material ordered for the battleships as possible, including their gun turrets. Churchill was unmoved, however, until the experiences of Battle of Heligoland Bight in August and the Battle of the Falkland Islands in December, seemed to demonstrate that high speed and heavy gun power was a potent combination and vindicated Fisher's long-held belief on the viability of the battlecruiser. These actions, plus pressure from Admiral Jellicoe, commander of the Grand Fleet, and Vice Admiral Beatty, commander of the Battlecruiser Force, caused Churchill to gain approval from the Cabinet to build two ships on 28 December.