The Government of the United Kingdom maintains intelligence agencies within several different government departments.
 The agencies are responsible for collecting and producing foreign and domestic intelligence, providing military intelligence, performing espionage and counter-espionage.
 Their intelligence assessments contribute to the conduct of the foreign relations of the United Kingdom, maintaining the national security of the United Kingdom, military planning and law enforcement in the United Kingdom.
 The three main agencies are the Secret Intelligence Service (MI6), the Security Service (MI5), and the Government Communications Headquarters (GCHQ).
The Security Service, also MI5 (Military Intelligence, Section 5), is the United Kingdom's domestic counter-intelligence and security agency and is part of its intelligence machinery alongside the Secret Intelligence Service (MI6), Government Communications Headquarters (GCHQ) and Defence Intelligence (DI).
 MI5 is directed by the Joint Intelligence Committee (JIC), and the service is bound by the Security Service Act 1989.
 The service is directed to protect British parliamentary democracy and economic interests, and counter terrorism and espionage within the UK.
The spy film genre deals with the subject of fictional espionage, either in a realistic way (such as the adaptations of John le Carré) or as a basis for fantasy (such as many James Bond films).
 Many novels in the spy fiction genre have been adapted as films, including works by John Buchan, le Carré, Ian Fleming (Bond) and Len Deighton.
 It is a significant aspect of British cinema, with leading British directors such as Alfred Hitchcock and Carol Reed making notable contributions and many films set in the British Secret Service.
Call for the Dead is John le Carré's first novel, published in 1961.
 It introduces George Smiley, the most famous of le Carré's recurring characters, in a story about East German spies inside Great Britain.
 It also introduces a fictional version of British Intelligence, called "the Circus" because of its location in Cambridge Circus, that is apparently based on MI6 and that recurs throughout le Carré's spy novels.
Control is a fictional character created by John le Carré.
 Control is an intelligence officer who acts as the head of "the Circus", the British overseas intelligence agency.
 He is a character in the novels "The Spy Who Came in from the Cold", "The Looking Glass War", and "Tinker Tailor Soldier Spy", and is referred to in several others, usually by association with le Carré's recurring protagonist George Smiley, who has served as Control's right-hand man.
Glenmore Stratton Trenear-Harvey (born 29 December 1940) is a British intelligence analyst who writes, broadcasts and lectures on the subjects of security, intelligence, espionage and terrorism.
 He is the editor-in-chief of the "World Intelligence Review", an associate editor of "Eye Spy" intelligence magazine, and publisher of "Intelligence Digest".
 Trenear-Harvey is an intelligence analyst for Sky News, and also broadcasts on NBC, CNN, Al Jazeera, France 24, Russia Today, and the BBC.
 He hosted the weekly show "Energy World" several times, on the satellite channel Press TV.
 He claims to receive regular briefings from Britain’s Secret Intelligence Service (MI6) and Security Service (MI5) and maintains contact with former (and he claims serving) intelligence officers of the American, British, and former Soviet security and intelligence services.
The Russia House is a spy novel by John le Carré published in 1989.
 The title refers to the nickname given to the portion of the British Secret Intelligence Service that was devoted to spying on the Soviet Union.
 A film based on the novel was released in 1990 starring Sean Connery and Michelle Pfeiffer, and directed by Fred Schepisi.
 The BBC produced a radio play starring Tom Baker.
Tinker Tailor Soldier Spy is a 1974 spy novel by British author John le Carré.
 It follows the endeavors of taciturn, aging spymaster George Smiley to uncover a Soviet mole in the British Secret Intelligence Service.
 Since the time of its publication, the novel has received critical acclaim for its complex social commentary and lack of sensationalism, and remains a staple of the spy fiction genre.
David John Moore Cornwell (born 19 October 1931), known by the pseudonym John le Carré ( ), is a British author of espionage novels.
 During the 1950s and the 1960s, he worked for both the Security Service and the Secret Intelligence Service, and began writing novels under his pen name.
 His third novel, "The Spy Who Came in from the Cold" (1963), became an international best-seller and remains one of his best-known works.
 Following the success of this novel, he left MI6 to become a full-time author.
Audre Lorde ( ; born Audrey Geraldine Lorde; February 18, 1934 – November 17, 1992) was a writer, feminist, womanist, librarian, and civil rights activist.
 As a poet, she is best known for technical mastery and emotional expression, as well as her poems that express anger and outrage at civil and social injustices she observed throughout her life.
 Her poems and prose largely deal with issues related to civil rights, feminism, and the exploration of black female identity.
 In relation to non-intersectional feminism in the United States, Lorde famously said, "Those of us who stand outside the circle of this society's definition of acceptable women; those of us who have been forged in the crucibles of difference -- those of us who are poor, who are lesbians, who are Black, who are older -- know that survival is not an academic skill.
 It is learning how to take our differences and make them strengths.
 For the master's tools will never dismantle the master's house.
 They may allow us temporarily to beat him at his own game, but they will never enable us to bring about genuine change.
 And this fact is only threatening to those women who still define the master's house as their only source of support."

Question: Who worked for both the Security Service and the Secret Intelligence Service, and began writing novels under his pen name, Audre Lorde or John le Carré?
Answer: David John Moore Cornwell