上海公共租界巡捕房
On 1 May 1907 he joined the Shanghai Municipal Police, as Assistant Superintendent of Police, heading the Sikh Branch for some years, before becoming Commissioner of Police in December 1925. On 1 October 1929 he was forced to resign after disputes about police effectiveness and reform. Barrett was appointed a Companion of the Order of the Indian Empire (CIE) in the 1919 Birthday Honours.