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: from the Turkish ambassador in London, reporting an interview with Churchill on his return from the Soviet Union and the Middle East, on August 28, returned from the Vice-Chief of the Naval Staff; a report on the Mediterranean: of German Air Force (GAF) measures against a possible convoy to Malta; and the First Sea Lord's (1SL) reply to the Prime Minister's (PM's) query on this.