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: of Kesselring's order of the day, that all are to stand firm, on April 19; and on the German Air Force's (GAF's) methods for attacking aircraft carriers, on April 19; and from the Chinese Legation in Berne, that Germany demands the right of passage through Switzerland, on April 17.