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 the Mediterranean: a German Air Force (GAF) report of an attack on a British naval formation on March 11; and on the Russian Front: that German ground forces repelled Soviet attacks on March 11; and that the GAF are to provide extra anti-aircraft protection for railways, from March 12.