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: that an Italian operation in east Bosnia has been deferred until April 25; that RAF reconnaissance aircraft were shot down on April 6 in the Crete area; that the 4th Air Fleet are to continue 'strangling' the Kerch Peninsula on April 10; and Naval Headlines, covering U-boat activities in the north Atlantic and Italian convoys in the Mediterranean.