MI6

The Secret Intelligence Service, also known as MI6 , is a British foreign intelligence service of the United Kingdom. Formed in 1909, it is tasked with covert overseas collection and analysis of human intelligence. 
==In TACITUS ==
In the TACITUS Saga, MI6 is the parent organization of the fictional Situational Assault Unit, an elite covert British intelligence and counterterrorism unit, designed to be the British counterpart of TACITUS. The unit travels around the world, targeting enemies of Great Britain on behalf of the British government. Much like the CIA, if any member of the Situation Assault Unit is captured or killed, the British government will deny any and all responsibility for the incident.