Today’s GCHQ is the product of over a century of organic development. Modern Signals Intelligence (Sigint) began in two small organisations at the start of the First World War and has evolved into an integrated intelligence and security organisation with a responsibility for defending UK interests worldwide.
In parallel with the development of the intelligence and security mission, a legal framework has developed to ensure not only that GCHQ operates within the law, but that ministerial and parliamentary oversight of GCHQ’s activities can provide reassurance of the legality and proportionality of what GCHQ does.
There has been an alphabet soup of abbreviations and designators for the national Sigint and Information Assurance organisations: Room 40, MI1b, GC&CS, LSIC, LCSA, CESD, CESG: GCHQ was adopted, first as a cover term for the Government Code and Cypher School in October 1939 when local people began to ask what the organisation was which had taken over Bletchley Park, and later, on 1 April 1946, as the official name for the organisation.
Under the Intelligence Services Act 1994, GCHQ became an autonomous department on its own statutory footing, with ministerial responsibility belonging to the Secretary of State for Foreign and Commonwealth Affairs.
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