It's been four years since the general U.S. release of Four Lions, Chris Morris' pitch-black satire about a crew of inept wannabe suicide bombers in the north of England, and almost five since the movie debuted at Sundance. Since then, as many as 500 British citizens have left their homes to join ISIS, the terrorist group seeking to establish a fundamentalist Islamic caliphate in the Middle East, with one 21-year-old British national, Hamzah Parvez, sending an online message home to fellow Muslims urging them to join him. "Are we content with eating Nando's every week?" Parvez asks, referring to the inexpensive Portuguese chicken chain ubiquitous on British high streets. "Come to the land of jihad and shout Allah."

The jihadi preoccupation with fried chicken features in Four Lions' opening scene, where ringleader Omar (Riz Ahmed) and his exceptionally dimwitted friend Waj (Kayvan Novak) are attempting to film propaganda videos railing against decadent Western imperialism. As Omar starts to use the Big Mac as a metaphor for cultural degradation, Waj interrupts: "Flippin' idiots. You could have gone Chicken Cottage, proper halal, bargain bucket, £6.99."

Four Lions takes Charlie Chaplin's quote about life being a tragedy in close-up and a comedy in long-shot and inverts it. As a concept, terrorism goes beyond abhorrence, but the day-to-day intricacies of it are another story, like the tale Morris tells about how Khalid Sheikh Mohammed once held up a television interview for two hours because he was trying to find an outfit that didn't make him look fat, or the British jihadists who ordered Islam for Dummies from Amazon before they left for Syria. While public instinct is usually to mythologize terrorists as fearsome bearers of impossible doom, frequently the reality, as Morris deftly demonstrates, is far less imposing.

52-year-old Morris is a cult figure in the U.K., partly because of his iconoclastic takes on subjects like pedophilia and drugs in the satirical news show Brass Eye, and partly because of his reclusiveness. Prior to the release of Four Lions in 2010 he refused virtually all interview requests as a matter of course, and has stayed out of the spotlight ever since, although he occasionally flies to Baltimore to direct episodes of Veep for Armando Iannucci (the pair collaborated on the spoof 1994 news show The Day Today). But during the period Morris was promoting Four Lions, his debut feature film, he gave unprecedented access to the media, talking over and over again about his motivations for making the movie. "It wasn't about getting the least likely subject for a comedy and then making a film about it, but the other way round," he told The New York Times. "I wanted to understand what was going on. Once I started reading I found things that made me laugh."

Waj, simple-minded Faisal (Adeel Akhtar), and wannabe rapper Hassan (Arsher Ali) seem motivated more by the promise of glory and a fast-tracked, "sweet VIP lounge" route to heaven than by any particular deference to Allah, whose name is rarely invoked in the film. Instead, martyrdom is more a mission to one-up kafirs, who aren't so much unbelievers as straw enemies. "Our plan is, right, to put a bomb on a crow and fly it into one of them towers filled with Jews and slags," says Faisal. "Let's do Boots," says Waj, referring to the drugstore chain. "They sell condoms that make you wanna bang white girls." In a furious invective against British culture, Omar rails against a lengthy list of enemies, including upmarket grocery stores, torture, Disneyland, dead Afghanis, and Gordon Ramsay.

The "lions" in the movie are four disaffected British men of Pakistani heritage and one white convert to Islam, Barry (Nigel Lindsay), who seems to be pursuing jihad as an outlet for his psychotically violent tendencies. None is particularly religious—Barry on more than one occasion suggests a mosque as a target for their attacks—and all seem to be almost catatonically stupid, except for Omar, even though he himself gets inspiration not from the Koran but from The Lion King. Omar's secular life in a comfortable house with his beautiful wife, Sofia (Preeya Kalidas), and his adorable son is deliberately juxtaposed with that of his brother, Mahmood (Mohammad Aqil), a deeply religious Muslim who tries to warn Omar away from violence but is criticized by Sofia for locking his own wife in a cupboard.

Morris' style as a writer and performer stretches from satirical to surreal, and the mix oddly seems to gel better with the subject matter in Four Lions than it did in previous works like Jam, where the fusion of dream-like vignettes and stream-of-consciousness absurdity tended to be more jarring than funny. During a scene in which Omar's brother is interrogated, a stern-looking policeman tells him, "We know a lot more than you think we do," before pulling a Weetabix biscuit out and brandishing it at him—a neat encapsulation of how ham-fisted British authorities can be when it comes to tackling home-grown terror. When Barry places screws methodically in a bomb, he names each one for a chosen enemy, muttering, "Jew. Gay. Fed. Sodomite. Gynecologist. Leonard Cohen."

Many of the film's references carry even more weight now than they did five years ago: Omar criticizes Barry for trying to set up the Islamic State of Tinsley (an English suburb), and later films a propaganda video in front of a black and white flag. The ultimate location for the group's terror plot (spoilers ahead) is the London marathon, in scenes that feel eerie to watch after Boston. When Omar and Waj fly to Pakistan to join a terrorist training camp, Waj films himself on his cellphone brandishing a machine gun so he can send videos home in which he's spraying bullets and billing himself as "Paki Rambo." There's even a guest appearance from a younger Benedict Cumberbatch playing a truly ineffectual hostage negotiator.

Morris has described his characters as Dad's Army terrorists: bumbling, incompetent, and prone to mistakes, but they're also just as isolated, aware of their own limitations, and desperate for glory as the World War II Home Guard was. Morris never specifies who or what has radicalized them, but he's clear on what makes each so susceptible to the vague promises of an inspiring and chastising figurehead, whether that's Omar or a preacher on YouTube. Even in its darkest moments—like Chekhov's bomb-vest, no improvised explosive device goes undetonated—the film resists the urge to blindly condemn each character (with the possible exception of Barry, who's truly a total nutjob). "I'm sorry lads," says Waj, as he faces a battalion of armed police. "I don't really know what I'm doing." He isn't the only one.