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 U-boat activity; from the Turkish minister in Bucharest, on Roumanian dissatisfaction with the British policy towards the Soviet Union, on January 21; and from the Japanese ambassador in Ankara, passing on German information on the low morale in Bulgaria following an Allied raid on Sofia.