In 1990, Margaret Thatcher gave a speech at the World Ministerial Drugs Summit, calling the substances an “insidious threat.” The Iron Lady wasn’t the only force fighting the war on drugs. With heroin addiction sweeping through the United Kingdom, a secret operative called Beta Projects placed undercover HM Customs and Excise officers into smuggling rings. Those who once stamped passports now posed as gangsters. A new show details the work of these embedded officers, led by the jaded detective Don (Steve Coogan). Legends is based on true events, and the character Guy (Tom Burke) is the real-life officer “Guy Stanton,” who worked in customs for 35 years and undercover for 11, constructing an alter ego in the process. “It’s very difficult to switch out and to just suddenly disappear,” the real Stanton told The Times of his life after drug-busting. “Unless you’re killed, of course.” —Maggie Turner