Flying Officer Sebastian ("Sas") Bernard de Mier was an airman of the Royal Air Force Volunteer Reserve who died during the Second World War.

He was born on 10 March 1911,[1] in Tlalpan, Mexico,[2] the son of Don Sebastian Bernardo, a diplomat, and Dona Maria Luz de Mier, daughter of Don Guillermo de Landa y Escandon. His mother later remarried, to William Arbuthnot-Leslie of Scotland,[3] and the family duly settled in Britain.[4] Prior his enlistment in the RAF, it had been reported, in March 1940, that he had accepted an approach from American colonel Charles Sweeney, who was endeavouring to organise a 'foreign legion' of airmen for service in Europe.[5]

Aged 31, Flying Officer de Mier, serving as an air gunner with 418 (RCAF) Squadron, died on 18 May 1942, when his Douglas Boston III bomber was lost over the Netherlands. He had married, in 1939, to Evelyn Richardson (Weil). His brother, William, served as an officer in the Gordon Highlanders and was taken prisoner on the fall of Singapore.[6][7]

He is buried in Dantumadeel General Cemetery, Damwoude.


  1. 1939 England and Wales Register [database on-line]. Lehi, UT, USA: Operations, Inc., 2018.
  2. "United States Border Crossings from Mexico to United States, 1903-1957," database, FamilySearch ( : accessed 24 September 2015), Sebastian De Mier, 02 Jun 1935; from "Border Crossings: From Mexico to U.S., 1895-1957," database and images, Ancestry ( : 2006); citing arrival port Brownsville Municipal Airport, Brownsville, Texas, NARA microfilm publication M1502 (Washington D.C.: National Archives and Records Administration, n.d.), roll 24.
  3. Proceedings of the Society of Antiquaries of Scotland, Volume 106, p. 165.
  4. The Times, Col E, p. 7: "Flying Offensive Sebastian de Mier". 9 October 1942.
  5. "Reaches Paris", The Windsor Daily Star, 4 March 1940.
  6. Barnato Walker, Diana (1994), Spreading My Wings: One of Britain's Top Woman Pilots Tells Her Remarkable Story, p. 58.
  7. The 2nd Gordon Highlanders in the Malayan Campaign and Captivity 1941-5, Retrieved 8 August 2013.


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