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 correspondence: a minute from Sir Alexander Cadogan to the Prime Minister (PM) concerning 2273: on the replacement of gas masks in the German armed forces indicating that their total strength was just under 5 million (report 2273 is not included).