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 contains a message from Group Captain Jones to Group Captain Winterbotham for the Prime Minister (PM); and the following reports: from the Japanese ambassador in Berlin, that the Allies are believed to be preparing for a decisive offensive, on October 12, also noting German views on Poland after the Warsaw rising; from the Chinese minister in Tehran, observing the Japanese realisation that their defeat is inevitable, on October 12; and Naval Headlines.