A BBC programme to be shown on BBC 2 television tonight at 9pm will show how high ranking British spies helped the Japanese to plan the Pearl Harbor attack.
One was Lord Semphill. He began aiding the Japanese during the Anglo-Japanese alliance. He played a crucial role in building up the Japanese carrier fleet during the 1920s and 30s. In 1939 he was working for the British admiralty. In 1941 he reported on discussions between Roosevelt and Churchill which showed much of the American fleet was deployed in the Atlantic and could not respond to an attack on Pearl Harbor. Despite knowledge of his treachery becoming known, the British took no action against him beyond a demotion.
The other spy was Frederick Rutland who also helped to develop the Japanese carrier fleet. Later he moved to Hawaii where he worked for US military companies whose secrets he sent to Tokyo. In 1941 he sent photographs of Pearl Harbor to Japan. He was detained during the war but never prosecuted. BBC Two - The Fall of Singapore: The Great Betrayal