MI6

MI6, formally the Secret Intelligence Service and often written SIS, is the United Kingdom's intelligence service, with a remit covering international affairs. It works alongside allied agencies whenever a problem crosses borders: during the Second World War, Chester Phillips had Peggy Carter coordinate the Strategic Scientific Reserve's work with MI6 in order to find the location of Hydra Headquarters. Its officers are handed a target individually and expected to run it themselves, as when Clive Reston was tasked with locating and capturing Spymaster and worked it through the NSA and then a trip to the United States.