Government Code and Cypher School: Signals Intelligence Passed to the Prime Minister, Messages and Correspondence

A file of signals intelligence reports, messages, and correspondence issued by the Government Code and Cypher School and sent by the head ('C') of the Secret Intelligence Service (MI6) to the Prime Minister, Winston Churchill. This file includes the following reports: Naval Headlines, covering German and Italian activity; of views of the Japanese ambassador in Berlin on Japanese collaboration with the Axis, on April 13; the Japanese minister in Budapest reports that Japan is urged to attack the Soviet Union, on April 10; that the Turkish ambassador in Tokyo was informed by the Japanese of a delay to the German offensive, on April 15; of a message from the Japanese Foreign Ministry to Berlin on Japanese-German exchanges on future plans, on April 15; and a letter to the U.S. Navy Department querying the source of sigint on Japanese intentions against the Soviet Union, of April 17.