Seagrim was born in
Ashmansworth,
Hampshire, England, on 24 March 1909. He was educated at
Norwich School, graduated from the
Royal Military College, Sandhurst, and joined the
British Indian Army, becoming an officer in the
19th Hyderabad Regiment. He was later seconded to the
20th Burma Rifles with the temporary rank of major, becoming an expert in several Burmese languages. When the
Japanese invaded Burma, he was given the task of raising irregular guerrilla forces from the
Karens and other groups. The British were driven from Burma by May 1942, and Seagrim and his force were isolated for a long time. Eventually
Force 136 dropped agents and wireless operators who made contact with his guerrillas in October 1943. Seagrim led Karens in a campaign of sabotage against the occupation. His force enjoyed much support from Karen civilians despite a series of brutal Japanese reprisal killings against Karen villages. His force was gradually wiped out by a concentrated Japanese manhunt. To prevent further bloodshed Seagrim surrendered himself to the Japanese forces on 15 March 1944. He and eight of his Karen companions were executed by the Japanese on 22 September 1944 in
Rangoon. For gallantry under captivity, he was posthumously awarded the George Cross in 1946. ==George Cross citation==