GCHQ

GCHQ is the United Kingdom’s signals intelligence agency, descended from the 1919 Government Code and Cypher School and the wartime codebreakers of Bletchley Park. Snowden documents revealed Tempora, its program tapping transatlantic fibre-optic cables to buffer vast volumes of raw internet traffic, and its access to NSA collection including PRISM. In 2015 the Investigatory Powers Tribunal ruled that GCHQ’s intelligence-sharing with the NSA had been unlawful for years, the tribunal’s first ruling against an agency in its history. Files tagged GCHQ document the cable-tap architecture, the UK-US intelligence relationship at the heart of Five Eyes, and the legal frameworks retrofitted around collection that was already occurring.