In August 1915, after recovering from his injuries, Elles was one of three officers specially selected by GeneralSir William Robertson, soon to be Chief of the Imperial General Staff (CIGS), the professional head of the British Army, to liaise with troops at the front and pass the information directly to the British General Headquarters (GHQ). In January 1916, as a General Staff Officer (GSO), Elles was sent by General Sir Douglas Haig, the Commander-in-Chief (C-in-C) of the BEF on the Western Front, to investigate the first tanks or "caterpillars" being built in England. He attended the first trials of "Mother" and reported back to Haig on its success. During the summer of 1916, Elles, who in June had been awarded the Distinguished Service Order (DSO),[4] was tasked to report back from the Somme, where the tanks were first used. Promoted to the temporary rank of colonel, Elles was appointed to head the Heavy Branch (the first tank units) of the Machine Gun Corps in France on 29 September 1916.[3]
Having seen the tanks achieve little success during the Battle of Passchendaele because of the exceptionally wet ground conditions of the autumn 1917, he pressed Haig to use massed tanks on the drier, open ground at Cambrai. On 20 November 1917 he personally led 350 tanks into battle at Cambrai in a Mark IV tank called Hilda, named after a favourite aunt.[5] Elles, promoted to brevet colonel in June 1918,[6] continued to command the Tank Corps until Germany's surrender in November 1918.[2]
The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Major General Hugh J. Elles, Royal British Army, for exceptionally meritorious and distinguished service in a position of great responsibility to the Government of the United States, during World War I. While Commanding the Tank Corps, British Expeditionary Forces, General Elles rendered invaluable service to the American Expeditionary Forces and to the cause in which the United States has been engaged.[7]