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 contains a message from C to General Sir Hastings Ismay and the Chiefs of Staff to see a BONIFACE extract: an extract from a Naval Headlines report (see 7237), making reference to gas and chemical warfare on July 20, and read to the Chiefs of Staff on July 27.