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 messages: from Hut 3 to the Code and Cypher School (CSS), from General Montgomery to the Prime Minister (PM), on March 28, communicating the severe defeat of the enemy, and that the Mareth line was captured (5 copies); and from the PM to Montgomery, on March 28, sending congratulations plus the latest intelligence (5 copies).