Part of Washington’s global military command and control system,  Croughton was originally set up to co-ordinate an attack by US nuclear bombers. It has since evolved into a state-of-the-art relay hub for some of Washington’s most sensitive material, including CIA agent communications.

"RAF" Croughton, the US Air Force base and CIA relay station near Brackley in Northamptonshire houses the 422nd Air Base Group whose function is to provide installation support, services, force protection, and worldwide communications across the entire spectrum of operations.

Croughton was named in documents leaked by the National Security Agency whistleblower Edward Snowden as playing a key support role in embassy-based spying. The base "has a secure data link to a US counter-terrorism facility in Djibouti used for drone strikes in Yemen while questions remain about the use of other US bases in Britain, in particular the National Security Agency eavesdropping facility at RAF Menwith Hill in North Yorkshire." The Independent