Thirty years after Dame Judi Dench first appeared on the silver screen as M, the head of British foreign intelligence agency MI6 in the James Bond universe, reality has finally caught up with fiction.Britain’s Prime Minister Keir Starmer on Sunday announced that Blaise Metreweli would succeed outgoing MI6 chief Richard Moore later this year, making her the first woman to lead the covert agency in its nearly 116-year-long history. Metreweli, 47, is currently leading MI6’s Q section, responsible for technology and innovation.Art imitates life, life imitates artMuch has been written about Dench being cast as M in GoldenEye, the 1995 Bond classic that introduced Pierce Brosnan as the eponymous British spy.Dench’s character was inspired by Stella Rimington, who in 1992 became the first woman to lead a British intelligence agency (she headed MI5). “There is now a woman at the head of the British secret service and this Bond film reflects that — quite rightly, in my view,” Dench had said in an interview.For a film franchise steeped in sexism, Dench being cast as M was significant. In her very first interaction with Bond in GoldenEye, M calls him “a sexist misogynist dinosaur” — overtly signalling the filmmakers’ intent to adapt to the times.Read | British PM announces first-ever female head of MI6: Who is Blaise Metreweli?But not much actually changed in the films. Introducing a female authority figure did not make Bond any less sexist, nor did it make any larger feminist point.That said, it would take MI6 another three decades to get a woman chief in reality — unlike two of its sister spy agencies, MI5 and GCHQ. MI5 has had Rimington and later Eliza Manningham-Buller as women chiefs, and GCHQ is currently headed by Anne Keast-Butler, its first woman leader.Story continues below this adAs per long-standing MI6 convention, Metreweli, a career intelligence officer who has also worked with MI5, will take over with the codename C. As MI6 chief, she will be the agency’s only publicly-named officer, and directly report to the Foreign Secretary (currently, David Lammy).How British spy agencies workThe United Kingdom has several intelligence agencies with different, sometimes overlapping, remits. Over the last three-and-a-half decades, they have somewhat emerged from the shroud of secrecy that covered them during the Cold War, providing more perspective on what they do, and how they operate.MI5: Military Intelligence Section 5, officially the Security Service, is the UK’s domestic counterintelligence and security agency. It traces its origins to the Secret Service Bureau formed in 1909. Its first chief, Vernon Kell, was a captain in the British Army, who would remain in-charge of the agency till 1940.The agency’s original remit was focussed on identifying and countering spies of Imperial Germany working on British soil, a mission that grew in importance during World War I (1914-18). The MI5 saw great successes in countering German spies during both World Wars, although its record against Soviet spies during the Cold War was more chequered.Story continues below this adIn the post-Cold War era, the bulk of MI5’s activities have been focussed on counter-terrorism. Rimington was the very first publicly-declared head of the agency, as well as the first person to pose openly for cameras. Today, MI5 is Britain’s least opaque security agency. The Intelligence Bureau is MI5’s Indian equivalent.MI6: Military Intelligence Section 6, officially the Secret Intelligence Service (SIS), is the UK’s foreign intelligence agency, tasked with the collection, analysis, and dissemination of foreign intelligence, as well as conducting espionage activities outside British territory.The agency too traces its origins to the Secret Service Bureau, specifically, its Foreign Section. The first chief of the SIS, Sir Mansfield Cumming, frequently signed his directives with the letter C, giving birth to a codename that remains in use till date.By the 1930s-40s, the MI6 emerged as the most effective intelligence agency in the world. It made its mark during World War II, when it conducted espionage operations behind German lines in Europe, and in Africa, Latin America, and Asia.Story continues below this adLike MI5, its record against the Soviets has been chequered: communist double agents had penetrated deep into the agency since as early as the 1930s. Nonetheless, it was a key player operating from the shadows throughout the Cold War, orchestrating coups, covert hit jobs, and gathering crucial intelligence which it routinely shared with the American foreign intelligence agency, the CIA.Official acknowledgement of MI6’s existence came in 1994. India’s Research & Analysis Wing (R&AW) has a similar remit as the MI6.GCHQ: The Government Communi-cations Headquarters (GCHQ) is specifically responsible for providing signals intelligence (SIGINT) to the British government and armed forces.Established after World War I as the Government Code and Cypher School (GC&CS), the GCHQ, while operating from Bletchley Park in Milton Keynes, cracked the German enigma code during World War II — an achievement that might have saved millions of Allied lives over the course of the war.Story continues below this adToday, it has two primary tasks: first, to gather and analyse communications and other SIGINT, and second, to secure the UK’s own communications and digital space against enemy attack.In 2013, GCHQ received considerable media attention when American whistleblower Edward Snowden revealed that the agency was illegally collecting online and telephone data within the UK.