A mysterious letter detailing a supposed Islamist plot to take over schools shocked Britain in 2014. But who wrote it? From Serial Productions and The New York Times, “The Trojan Horse Affair,” an investigation that became bigger than we ever imagined. All eight parts are available now, wherever you get your podcasts. Search "The Trojan Horse Affair." To learn more about upcoming episodes of METRO and get a look behind the scenes, find us on Instagram, TikTok, and Facebook by searching “Serial Productions”. Have a story pitch, a tip, or feedback? Email us at serialshows@nytimes.com. Hosted by Simplecast, an AdsWizz company. See https://pcm.adswizz.com for information about our collection and use of personal data for advertising.