Sempill, Japan, and Pearl Harbor

Lord Sempill (1893–1965) was the subject of extended investigation by the British Security Service (MI5) between World War I and II. A distinguished aviator, he was suspected of disclosing classified information to the Japanese over the years 1923 to 1925 and 1939 to 1941. MI5’s investigation was inconclusive. But with the progressive release of agency materials from the late 1990s, Sempill attracted high-profile interest from historians and media alike. In 2012, he was labeled “the traitor of Pearl Harbor,” a canard with implications for the integrity of the early Atlantic alliance. This fresh study of a major early-modern counterespionage case reassesses Sempill in relation to his professional and political milieu and explores his Japanese connections as Tokyo moved from guarded friendship to challenge and aggression in the climacteric year 1941. Notwithstanding his admission of a technical breach of the Official Secrets Act in 1925, the evidence overall does not support the prevailing view of Sempill as a spy who betrayed British and American interests

Alliance · Archaeology · Criminology · Espionage · Friendship · Mythology · Pearl · Political science · Politics · Social science · Sociology · World War II · Classics · History · Intelligence, Security, War Strategy · Law · Military History and Strategy