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: a message for Sir Alexander Cadogan from C; a note from the Prime Minister (PM) for the Secretary of State; and the text of a report from the Italian ambassador in Istanbul on German-Turkish trade negotiations and Turkey's intentions from October 2.