MI6 (SIS)
Britain's foreign intelligence service, the world's oldest, which denied its own existence until 1994 and inspired James Bond while quietly running real spies.
MI6 is Britain's foreign intelligence service, and for most of its existence the British government flatly refused to admit that it existed. Officially it is the Secret Intelligence Service, or SIS; the old designation 'Military Intelligence, Section 6' stuck in the public mind and never left. Founded in 1909, it is the oldest continuously operating foreign-intelligence agency in the world, and it is the service that gave the world James Bond, a fictional glamour that its real officers have spent a century both exploiting and living down.
1909 and the man called C
The Secret Service Bureau was set up in 1909 amid a spy panic about Imperial Germany and soon split into a home section, which became MI5, and a foreign section, which became MI6. Its first chief was Mansfield Cumming, a naval officer who signed his letters with a single green-inked 'C.' Every chief since has been called C, not M as in the films, and the initial is now the formal shorthand for the head of the service. The job is a real one, publicly named, sitting atop an organization Britain long pretended did not exist.
The moles and the myth
MI6's actual history is grittier than its fiction. In the Second World War it ran deception schemes and agent networks across occupied Europe and sat close to the codebreaking triumph at Bletchley Park. Then came its deepest wound: the Cambridge Five, upper-class Britons recruited by Soviet intelligence in the 1930s. Kim Philby rose to become MI6's head of counter-Soviet operations while secretly working for Moscow, betraying agents to their deaths before defecting in 1963; Guy Burgess and Donald Maclean had already fled to Moscow in 1951. The scandal gutted trust between British and American intelligence for years and became the template for every fictional mole story since.
Out of the shadows
For most of the twentieth century the government would neither confirm nor deny that MI6 existed. That changed only in 1994, when the Intelligence Services Act put the service on a legal footing for the first time and openly acknowledged it. The same year it moved into its unmistakable headquarters at Vauxhall Cross on the Thames, a green-and-sandstone ziggurat that promptly became a film star, blown up on screen more than once while quietly housing the real thing. An agency that had spent 85 years denying its own existence now advertises its address.
What it actually does
Stripped of the mythology, MI6 is a comparatively small service focused on human intelligence: recruiting and running foreign agents to steal secrets that satellites and intercepts cannot reach, plus limited covert action, all overseen by ministers and Parliament. Its closest partner is the American CIA, a relationship forged in wartime, nearly wrecked by Philby, and rebuilt into one of the tightest intelligence alliances in the world, anchored in the Five Eyes network. The first big joint operation of the two services was the 1953 coup in Iran, which MI6 proposed after Tehran expelled its officers and the CIA then ran on the ground. The gap between the Aston Martins of the screen and the patient, deniable work of the real service is the point: the best of it is never seen, which is exactly how a service that denied its own existence for most of a century prefers to operate.