Special Operations Executive
The Secret Intelligence Service, sometimes known as MI-6 (Ministry of Intelligence-Division Six), 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 assigned himself the title 'C' and his successors have done so ever since.
When Europe was occupied by the Nazis, Sir Winston Churchill helped to create the Special Operations Executive on June 6, 1940-a significant date-with a letter to General Hastings Ismay, authorizing: "A proper system of espionage and intelligence along the whole coasts, to harass the enemy from behind the lines". The Special Operations Executive (SOE) was established and drew developing members from the then Section D of SIS. Afterwards recruits for SOE came from any and every aspect of life.
Other than a major concerted invasion, there was little hope of driving the Nazis out from outside the continent. What was needed was a network of resistance supplied and controlled from London. Section F would deal with occupied France for sabotage, the organization, training, arming and support of resistance. Operationally, F section was controlled by Col. Maurice Buckmaster. There was also DF, which dealt with escape lines and RF which helped De Gaulle's resistance organization.
SOE was highly secret and known to no one outside of the organization, and there was little conversation between the individual sections. The operational files of SOE are still classified today. SOE was dissolved in 1946. Some SOE members returned to the SIS as management in time for three decades of the Cold War. The headquarters of F Section was at 64 Baker Street in London.
Source: MI6: Secret Intelligence Service, 85 Vauxhall Cross, London, SE1, England