## Overview The Secret Intelligence Service (SIS), widely known as MI6 (Military Intelligence, Section 6), is the United Kingdom’s primary foreign intelligence agency, specializing in the covert collection, analysis, and dissemination of human intelligence from outside British territory[1][3][5]. Unlike its sister agency MI5, which focuses on domestic security, MI6 operates exclusively overseas, gathering information to inform UK policy, protect national security, and support international allies[1][8]. Its headquarters, a prominent feature on London’s South Bank, have been located there since 1994, though the organization’s existence was only officially acknowledged that same year[1]. ## History MI6 traces its roots to the Secret Service Bureau founded in 1909, initially to monitor German naval activities before World War I[1][8]. It was formally constituted in its current structure in 1912 under Mansfield Cumming, expanding rapidly during both World Wars[3][8]. The “MI6” label became popular during World War II, but the agency’s official name remains the Secret Intelligence Service[1][3]. For much of the 20th century, MI6 was regarded as one of the world’s most effective intelligence services, playing pivotal roles in both World Wars and the Cold War, including operations against Soviet espionage and involvement in notable geopolitical events such as the 1953 Iranian coup[3][8]. ## Key Achievements MI6’s successes are often shrouded in secrecy, but several notable operations have come to light. During World War II, its intelligence-gathering was crucial to Allied efforts, and in the Cold War, it monitored global communist movements[3][8]. More recently, MI6 provided critical intelligence ahead of Russia’s 2022 invasion of Ukraine, shared actionable information with Ukrainian partners, and helped thwart terrorist plots and major financial frauds targeting the UK[5]. The agency’s work in counter-terrorism