Lieutenant Colonel Dr. Anthony St. Clare Rex de Costa, MBE, CAVF (15 June 1920 - 9 April 1971) was a renowned Sri Lankan medical doctor and soldier.

He was married to his cousin Doreen de Costa nee Gunathilake and four children Marcel, Cheryl, Rex and Eric.

After his death the family was involved in community work in the town of Deniyaya and had close links to his old regiment, 2nd(V) Sri Lanka Army Medical Corps.

Bandaranaike became prime minister, he disbanded the Ruhunu Regiment as he considered it loyal to the previous UNP government.

Lt. Col. de Costa requested a transfer to his old unit the Ceylon Army Medical Corps, which was turned down.

For his service he was appointed a Member of the Order of the British Empire by HM Queen Elizabeth II and retired to a quiet life to his family home in Deniyaya in 1967.

Since the insurrection had taken the Ceylon Government by surprise many of the small police stations in rural areas were unprepared and overrun in the initial days with many constables and officers killed.