Person Open DS/UK/3605 Sempill; Lord; William Francis Forbes- (1893-1965); 19th Lord Sempill AFC, AFRAeS; British peer, traitor Sempill William Francis Forbes- Lord 1893-1965 British peer, traitor Male

William Francis Forbes-Sempill, 19th Lord Sempill AFC, AFRAeS, (24 September 1893 – 30 December 1965) was a British peer and record-breaking air pioneer who was later shown to have been a traitor who passed secret information to the Imperial Japanese military before the Second World War. Educated at Eton, he began his career as a pilot in the Royal Flying Corps and then served in the Royal Naval Air Service and Royal Air Force during the First World War. In 1921 Sempill led an official military mission to Japan that showcased the latest British aircraft. In subsequent years he continued to aid the Imperial Japanese Navy in developing its Navy Air Service. However in the 1920s Sempill began giving military secrets to the Japanese. Although his activities were uncovered by British Intelligence, Sempill was not prosecuted for spying and allowed to continue in public life. The decision, which was taken at highest levels of government, was based on several factors. Firstly it would have revealed British successes in decoding Japanese communications and secondly he was part of the British Establishment with family links to the Royal Family. He was eventually forced to retire from the Royal Navy in 1941 after being discovered passing on secret material to Tokyo shortly before Japan declared war in the Pacific. International Standard Archival Authority Record for Corporate Bodies, Persons and Families - ISAAR(CPF) 2nd edition - ICA 2004 ISBN 2-9521932-2-3 National Council on Archives, Rules for the Construction of Personal, Place and Corporate Names, 1997 Yes RAHSkeyte 1/2/2013 Rachael.Fragola 3/1/2022 eb261ccc-7707-42ae-99f6-0431c6d3fd63