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 Russian Front: of the German Air Force's (GAF's) combat plans for March 19; that the 1 Air Corps is to carry out intensive attacks against 4 Soviet cities east of Kharkov, using Stalino as a forward deployment base; and Naval Headlines.