Government Code and Cypher School: Signals Intelligence Passed to the Prime Minister, Messages and Correspondence

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: a Naval Headlines report covering German U-boat activities; a report that the battleship Tirpitz was preparing for torpedo firing trials; a report that German patrol vessels had been alerted to prevent Norwegian blockade runners from breaking out; and Italian reports that the battleship HMS Nelson and the aircraft carrier HMS Ark Royal left Gibraltar sailing eastward on September 16.