branch of the british government responsible for the collection and analysis of foreign intelligence.
The function of this government service is primarily espionage, the obtaining of accurate information from the enemy by means of spies or agents; double agents generally work for MI-5, the British internal security agency. Cooperation between both services was necessary when working with enemy spies who were uncovered in Great Britain and persuaded to work for the British from then on, thus double-crossing their original masters. Other agencies included primarily the Admiralty, the Air Force, the Home Office, and the Foreign Office; in both World War I and World War II, university faculty members and special professions were inducted into the intelligence services. After the last war, MI-6 continued to work in the Middle East, as did the U.S. Central Intelligence Agency (CIA).
Roosevelt, Kermit. Countercoup: The Struggle for the Control of Iran. New York: McGraw-Hill, 1979.
Stevenson, William. A Man Called Intrepid: The Secret War. New York: Harcourt Brace, 1976; reprint, New York: Lyons Press, 2000.
West, Nigel. MI6: British Secret Intelligence Service Operations 1909–45. New York: Random House, 1983.