On 27 September 1870 he was commissioned into the
1st Yorkshire (West Riding) Artillery Volunteer Corps as a
first lieutenant, a rank replaced by that of lieutenant during
British Army standardisation in 1871. The 1st Yorkshire (West Riding) Artillery Volunteer Corps was a
Volunteer Force coastal artillery unit formed at
Leeds in 1860 and armed with 32-pounder guns. Elliott-Cooper was promoted to
captain on 5 June 1875 and
major on 16 April 1879. He resigned his commission as a major on 27 February 1886 and was permitted to retain his rank and continue to wear the uniform. Elliott-Cooper later returned to the army by serving in the
Engineer and Railway Staff Corps, an unpaid volunteer unit which provides technical expertise to the
British Army. He was commissioned into this corps as a
lieutenant colonel on 6 January 1900. He was awarded the
Volunteer Officers' Decoration on 15 November 1904 in recognition of his twenty years service as a volunteer officer. Elliott-Cooper continued in the Engineer and Railway Staff Corps as a lieutenant colonel after that corps' transferral from the Volunteer Force to the newly formed
Territorial Force on 1 April 1908. He was made Commandant of the corps on 27 July 1912 and promoted to the honorary rank of
colonel. He resigned his commission with the corps on 21 March 1914 and was again permitted to retain his rank and wear the uniform. During the
First World War he was chairman of the ICE War Office Committee and of the
War Office Committee of Hutted Camps, a service for which he was rewarded with an appointment as
Knight Commander of the Order of the Bath on 1 January 1919. == Personal life and death ==