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 correspondence: the Japanese ambassador in Berlin informs the Japanese ambassador in Ankara about Japanese-German negotiations for a Three Power (Axis) declaration on India; the Japanese ambassador reports Hitler's intentions in building up the U-boat fleet, on March 29; and the Japanese ambassador in Berlin reports Ribbentrop's statements about Germany's war aims including the invasion of the Near East and the Indian Ocean.