Mass surveillance in the United Kingdom

The use of electronic surveillance by the United Kingdom grew from the development of signal intelligence and pioneering code breaking during World War II. In the post-war period, the Government Communications Headquarters (GCHQ) was formed and participated in programmes such as the Five Eyes collaboration of English-speaking nations. This focused on intercepting electronic communications, with substantial increases in surveillance capabilities over time.

Source: Wikipedia — Mass surveillance in the United Kingdom (CC BY-SA 4.0)