A file of correspondence and intercepted communications concerning breaches of security. The documents include several letters warning about cavalier treatment of confidential sources of information, posing a threat to their existence, and several more complaining about similar behaviour regarding classified documents. The file also contains a copy of an intercepted telegram sent to Tokyo in 1940 by the Japanese ambassador in Cairo, giving information about Anglo-French strategy in the Mediterranean gleaned from conversations with senior generals, along with British orders restricting conversations with Japanese diplomatic personnel.