The Secret Intelligence Service, sometimes known as MI6, originated in 1909 as the Foreign Section of the Secret Service Bureau, under RNR Commander, later Captain, Sir Mansfield Cumming, which was responsible for gathering intelligence overseas. By 1922 Cumming's section had become a separate Service with the title SIS. Cumming signed himself 'C' (his successors have done so ever since).
The Special Operations Executive (SOE) was established in 1940, partly from the then Section D of SIS. After the War it was disbanded and some of its members were reabsorbed into SIS.
With the passing of the Intelligence Services Act, SIS was placed on a statutory footing under the Foreign & Commonwealth Secretary to whom it is responsible for all aspects of its work. The Act defines the functions of the Service and the responsibilities of its Chief, as well as establishing control and oversight arrangements.
The Service's principal role is the production of secret intelligence in support of Her Majesty's Government's security, defence, foreign and economic policies within the framework of requirements laid upon it by the JIC and approved by Ministers. It meets these JIC requirements for intelligence gathering and other tasks through a variety of sources, human and technical, and by liaison with a wide range of foreign intelligence and security services. Specific operations are subject to longstanding procedures for official and ministerial clearance.