Lieutenant Colonel Warr was commissioned into the Australian Army in 1947, after graduation from the Royal Military College, Duntroon. Since that time he has either served with the Royal Australian Regiment or held staff appointments in Australia or abroad. When the Fifth Battalion, The Royal Australian Regiment, was formed Lieutenant Colonel Warr was Second in Command until September I 1965, when he was appointed Commanding Officer and the unit was warned for movement overseas. As Commanding Officer he was responsible for the training and welding together of both regular soldiers and national servicemen into an efficient combat unit in a short period of time. During a year's service in Vietnam, the Fifth Battalion, The Royal Australian Regiment, was in almost continual contact with the enemy whilst executing offensive patrol tasks, search and destroy missions, and cordon and search operations. The techniques for these latter operations were developed so successfully by Lieutenant Colonel Warr that they have been accepted as standard procedures in the First Australian Task Force.
Lieutenant Colonel Warr was responsible for the planning and execution in detail which is so necessary for successful operations by a battalion group in air mobile operations. His thorough preparation and orders, his sound tactical knowledge, his calmness and leadership under fire was largely responsible for the accomplishments of the Fifth Battalion, The Royal Australian Regiment, in Vietnam.