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 on North Africa: that German Air Force (GAF) fighter and bomber reinforcement units are to move to forward aerodromes, on May 18; and on North Africa: the Chief of the Air Staff's (CAS's) reply to the Prime Minister's (PM's) query and 987/T16; and CAS's reply to the PM's query (not included).