The origins of GCHQ date back to before the First World War.
With the development of radio communications in the early part of the 20th century, it was clear that radio technology would play a vital part in any conflict… So the UK government set up a Signals Intelligence service to intercept other countries’ radio transmissions.
During the First World War these teams successfully intercepted a wide range of German transmissions… And in 1919, the Government Code and Cipher School… GC&CS… the original name of GCHQ… was founded.
During the 1930s… GC&CS began to expand as the prospect of another war increased.
When war broke out in 1939, 180 members of GC&CS moved to Bletchley Park. By 1945, their work had become so vital to the war effort that the service had grown to around 10,000 people.
During the war, with successes such as the Bombe and Colossus, GC&CS played a major role in victory… And some historians claim its work shortened the war by up to two years.
The post-war era saw a shift in emphasis, as GCHQ began to play a key role in the Cold War.
The threat from the Soviet Union was very real throughout this period.
GCHQ’s recognised leadership in Signals Intelligence meant that it was at the forefront of activities to combat the Soviet threat.
Technical advances such as transistors and miniaturisation had a major effect on GCHQ’s work. In the 1970s we continued to be pioneers. Clifford Cocks and Malcolm Williamson, building on the work of James Ellis, developed public key cryptography – a fundamental security method that underpins a range of internet standards.
Due to the secrecy of our work, their discovery was classified until 1997 and an American team were credited with discovering the method – four years after Cocks and Williamson had got there first.
Today, our world is becoming increasingly dependent on the Internet. And we face more cyber threats on a daily basis than we ever have. This means our mission continues to evolve alongside it.
The way we achieve that mission is laid out in the Intelligence Services Act, or ISA. This makes sure we always operate within UK law and for three reasons. These are to only act, firstly in the interests of national security… secondly, in the interests of the country’s economic well-being… and finally, to support the prevention or detection of serious crime.
So, no matter how our mission evolves, our goal is always the same… to ensure the UK's people, businesses and interests remain safe and secure.