The sting: "The Day Shall Come"

I whisper this, given the adoring fanbase and the place the film has assumed in the pantheon of this century's foremost cult movies, but for all its much-quoted dialogue and provocative ideas, Chris Morris's directorial debut Four Lions struck these eyes as stubbornly televisual, like an extended pilot for an especially black-comic Channel 4 sitcom. (Telling that it gathered more reputational momentum once it appeared on DVD and then TV, where its shortcomings of scale were less obvious.) Morris's follow-up The Day Shall Come has as its very first shot a sweeping helicopter survey of a bustling North American coastline (actually the Dominican Republic, passing for Miami). Ah, fab, you think: Morris, the great satirist of our time, is finally making movies now - the only doubt, albeit one that swells over the course of the film, is that this is exactly the same panorama that opened countless episodes of CSI: Miami. What follows is certainly more grounded, as perhaps befits a wild goose chase. The Day Shall Come's main business is a based-on-actual-cases entrapment, of the kind US law enforcement has apparently been keeping itself busy with in the lull following the War on Terror: setting up latter-day black revolutionary Moses Al Shabazz (Marchánt Davis) with a fake sheik and fake nukes so as to make a bust that will keep FBI chiefs happy. Jurisdictional fallout from a collision of worlds, people making life unnecessarily difficult for themselves: all this is prime satirical real estate, and yet not so very far from the territory Morris has covered in his years directing episodes of Armando Iannucci's HBO show Veep. Could it be that Morris has but made a leap from directing a film that looks like British TV to a film that looks like American TV?

At the very least, Moses is a character singular enough to build a series around: a dingbat whose proclamations of black power are undermined by the tricorn hat and homemade chainmail (seemingly fashioned from old shower curtains) he insists upon wearing in public. (Instead of guns, he vows insurrection via toy crossbow, and comes to conduct all his official duties on horseback. Even when indoors.) We get some idea of what a deadbeat dad he is from a phone conversation in which he promises to bring his young daughter a box of doughnuts for her birthday: the girl's wary response is to ask "Will it just be the holes again?" The gag sustaining The Day Shall Come is that Moses is a harmless fool; as the crack FBI agent tracking him (played by Anna Kendrick, proving as much of a whizz with this dialogue as Anna Chlumsky has been on Veep) observes, "he has all the threat signature of a hot dog". Still, her superiors insist on pursuing him all the same, and that pursuit is where the movie plays to the usual Morris strengths. A dream team of script collaborators, including the eminent Jesse Armstrong (Succession, Peep Show) and Veep's Sean Grey and Tony Roche, keep throwing choice bits of phrasing our way (I chuckled disproportionately at the revelation one character was wearing an "orthopaedic clog"), while Morris busies himself setting up sight gags that rival any isolated frames he and Michael Cumming arrived at in the course of Brass Eye: a flash on a publication we're told is called Al-Qaeda Magazine (cover story: "Make Warheads Out of Cookie Dough"), a priceless CCTV shot of Moses's horse standing balefully in the FBI parking lot. When Moses, in full batshit regalia, invites the phoney Islamic State contact to "take a seat on the table", it feels like a distillation of three decades of Morris's absurdist methodology.

Where the film falls down - where it becomes not quite a film - is in its common-or-garden framing and blocking, in connecting up these flickers of inspiration into a properly moving picture; here, Morris starts to resemble Iannucci without the budgets that get you fully-fledged art and production design. The Day Shall Come feels a little hamstrung by having to play out, tentatively, on actual locations: there aren't enough extras to fill each frame with a convincing sense of life, and the leads only seem to have walked into these rooms five minutes before the cameras rolled. Morris is still filming sketches, where the movies demand detailed, lived-in portraits. He's getting more out of these carefully controlled conditions than he did first time round - the concluding siege at a donut shop expands (just) on the chicken shop material in Four Lions, even if it finally feels too small for a pay-off - but you keep catching him playing safe, as if he's unsure of the world he's stepping into, which the fearless Morris who ransacked our media hubs in Brass Eye and Nathan Barley wasn't. The result here is to entrap a smart and funny piece of writing within a brittle delivery system, too guarded to attempt the great leap Iannucci's The Death of Stalin made in going from amusing to chilling (or, indeed, that which Spike Lee's similarly pitched BlacKkKlansman made in going from blithe to angry). It may say something about the difference between artforms that Morris, a prodigious talent who took radio and television by storm, has found the cinema a far tougher nut to crack. (Iannucci, currently being toasted for his new David Copperfield, has found it easier, but then he was directing long before Morris.) The Day Shall Come is more consistent than its patchy predecessor - Veep editor Billy Sneddon picks up any comedy slack, engineering one superb gag involving Denis O'Hare, a lift and a coffee cup - but Morris has yet to make a movie as truly radical or arresting as his small-screen work. That day may still come.

The Day Shall Come is now playing in selected cinemas.