Pre-Independence He was commissioned in the
British Indian Army on 15 July 1938 from the
Indian Military Academy, Dehradun. As was customary, on 10 August 1938 he was attached to a battalion of a regular
British Army regiment, the 2nd
Worcestershire Regiment, for a period of one year prior to his official appointment to the Indian Army. He served in 7/10 Baluch during the
Burma Campaign. Dunn attended
Staff College, Camberley in 1945, and commanded a Gorkha battalion from November 1946.
General officer In September 1961, he was promoted to the acting rank of
major general and appointed Chief of Staff,
Southern Command, with
Lt Gen Jayanto Nath Chaudhari, OBE, as GOC of the Command. Over the 1960s, he served as the Colonel of the Regiment for the
3rd Gorkha Rifles. He succeeded Maj Gen Yadunath Singh, and was himself succeeded by
Lt Gen Sagat Singh. On 17 December 1962, he was given command of an infantry division. In January 1964, he was appointed Deputy Chief of General Staff (DCGS), He was then appointed Director of Staff Duties (DSD) from that date until April 1965, when he commanded troops in the
Rann of Kutch following Pakistan's
Operation Desert Hawk. ==Dates of rank==