GCHQ

The go-to intelligence expert and author of MI6 has "provided the clearest review of GCHQ and its predecessors in a publicly available book" (Firetrench).Signal intelligence is the most secret, and most misunderstood, weapon in the modern espionage arsenal. As a reliable source of information, it is unequalled, which is why Government Communications Headquarters, almost universally known as GCHQ, ...