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: an estimate of the maximum possible supply traffic from Italy to Benghazi, with the ratio of German to Italian supplies to be loaded, on April 28; and the Japanese ambassador in Berlin quotes Ribbentrop's letter to Rashid Ali, on April 24.