Eycott-Martin was
commissioned on 27 October 1915, at the age of 18, as a second lieutenant in the
Royal Engineers from the
Royal Military Academy, Woolwich. After being seconded to the
Royal Flying Corps, he was appointed a
flying officer on 29 March 1917. In May 1917, he was posted to 41 Squadron A week after joining the squadron, he crashed a
Royal Aircraft Factory FE.8 during takeoff. On 24 May 1917,
Flight Newsletter reported Eycott-Martin had wounded, but no date was given for the wounding. It seems likely he was injured in the takeoff accident. On 1 July 1917, Eycott-Martin was promoted to lieutenant in his home unit, the Royal Engineers. On 7 February 1918, he was reassigned to 66 Squadron in Italy. In short order, he won his first two aerial victories. Then, on 30 March 1918, he and
Alan Jerrard were
wingmen to
Peter Carpenter on the well-known occasion when Jerrard won his
Victoria Cross. In that same action, Eycott-Martin was credited with two victories; on 5 April 1918, he was subsequently awarded a
Military Cross for his role in this combat. Eycott-Martin's victory string culminated at eight on 22 June 1918. On 13 July, he was temporarily promoted to captain; he almost certainly simultaneously became a
flight commander. Eycott-Martin's MC was finally
gazetted on 16 September 1918. His citation read: :Lt. Harold Ross Eycott-Martin, R.E., R.A.F. :For conspicuous gallantry and devotion to duty. In a patrol with two other machines he attacked nineteen of the enemy. Of the six enemy aircraft destroyed on this occasion he destroyed two. On two other occasions he destroyed an enemy machine. ==Post World War I==