It’s not difficult to guess at some of the influences absorbed into Harris Dickinson’s raw character study, Urchin — the bleak nihilism of Mike Leigh’s Naked; the unvarnished realism of Ken Loach; the immersive textures as well as the loose-limbed vitality of Josh and Benny Safdie’s Heaven Knows What; the subjective realism, grubby poetry and surreal interludes of Gus Van Sant’s early films, Mala Noche, Drugstore Cowboy and My Own Private Idaho.

That’s not to say the English actor’s feature directing debut is derivative or doesn’t reveal his own voice. Any first-time filmmaker capable of distilling his inspirations into a highly personal portrait of the kind of life on the edges of society he has clearly observed firsthand is a talent.

Dickinson’s protagonist, Mike, is an addict trying — with fluctuating degrees of commitment — to break the pattern of self-destruction that seems baked into his DNA. Neither the writer-director nor Frank Dillane, who plays Mike with nervy volatility offset by insouciant charm and humor, courts our sympathies, even as the film shows unquestionable compassion.

Mike is a fuck-up who’s chronically dishonest and quite often a selfish asshole, capable of violence when he’s at his most desperate. He’s the kind of mess most of us just quickly walk by on the street and pretend is invisible. Perhaps the key achievement of Urchin is that it makes us see him and feel for his struggle.

The director grew up around people battling addiction and has worked with charities dedicated to homelessness in his local East London community for several years. The character of Mike was drawn from a handful of people Dickinson encountered — some he had been close to and some through his involvement with support groups. That connection no doubt adds to the authenticity of Dillane’s performance.

We first see Mike on what seems a typical morning, waking up in a daze on the pavement to the booming voice of a Bible-thumping street preacher. He scowls at her as he ducks down an alley to retrieve his rucksack from behind a dumpster, then takes up a spot panhandling on a busy corner, where people mostly ignore him. He talks his way into a restaurant to charge his phone but gets kicked out when he starts falling asleep at the table.

There’s almost a documentary aspect to these early scenes. Dickinson gives us nonjudgmental access to the day-to-day existence of one among any number of unhoused addicts, while Dillane presents Mike with all the prickly edges of a societal reject. Without ever resorting to melodrama or framing Mike as simply a casualty of an unforgiving system, the actor gives subtle indications of his intelligence — of potential that at some point slipped away as he found illusory refuge in drugs.

Mike gets into a brawl when Nathan (Dickinson, uncredited), a fellow addict also living rough, steals his wallet and blows all his cash. A well-meaning stranger breaks up the fight and offers to buy him some lunch. But Mike throws the man’s kindness back in his face by knocking him out and lifting his watch and wallet. Mike is swiftly arrested, and when he claims self-defense, a cop dryly points out that the entire incident was captured on CCTV. Dillane’s “Oh” is priceless.

That entire section unfolds with livewire energy, pumped up by Alan Myson’s driving techno score and by the shock of the assault. At this point in the narrative, when Mike is sentenced to 14 months jail time, more conventional addiction dramas would dig into the trauma of incarceration and the agony of substance withdrawal.

But that part of Mike’s experience is only of interest to Dickinson in so far as it lobs him back into the system when he’s released early seven months later. All we see of his spell in prison is a brief intake scene, one of the movie’s moments of unexpected humor, in which Mike amusingly whines about a guard’s cold touch, asking him to warm up his latex glove during a strip search.

Prison time also prompts one of a handful of magical realism flourishes — some of them better integrated than others — when Mike is showering, and the camera follows the soapy water down a drain, into the fiery bowels of the earth and beyond, entering a cosmic void with brightly colored amoebic forms floating around. The most significant of these fantastical detours is the recurring motif of Mike seeing visions of a woman who possibly represents his biological mother.

Dickinson shifts the tone in Loachian scenes with a parole officer and later a counselor. Having bounced around uncaring foster homes as a child, Mike maintains minimal contact with his adoptive parents and is skeptical about how much help the authorities can provide with his rehabilitation. He seems sincere in his desire to stay clean, but whether his big talk about wanting to start a limo service is a pie-in-the-sky boast or something he believes he could make happen remains ambiguous.

Dillane often conveys a sense that Mike is performing the role that’s expected of him in these encounters, possibly even trying to persuade himself that he can stay out of trouble. But he does appear to show genuine remorse at the end of a terrific scene in which the counselor sits him down with his assault victim.

Mike moves into temporary hostel housing and gets a restaurant job as a junior chef. At night in his austere room, he also starts listening to meditation tapes, on which a woman’s soothing voice spouts self-help platitudes like: “You’re in the driver’s seat. You’re going to be just fine… The road is clear. Each decision is yours.” Does he really buy into this or is he just going through the motions in order to be able to say the right thing at parole check-ins?

Again, Dillane skillfully teases out the ambiguity, and more than once Mike acts like he’s owed everyone’s sympathy, making him almost as entitled as he is at-risk. Before long, his head is not in the restaurant job, and his violent impulses resurface. He gets work picking up litter from public parks and sparks up the beginnings of a romance with French co-worker Andrea (Megan Northam), who lives in a caravan.

Unaware he’s in recovery, Andrea gives Mike some ketamine while they are out partying one night, an exhilarating sequence in which they whirl around the capital to the sound of the ‘80s French synth-pop banger “Voyage Voyage,” by Desireless. But that high reopens the door to Mike’s drug and alcohol abuse, dismantling any tentative stability he has achieved once he starts getting wasted with strangers.

Dillane’s helplessness in these scenes is haunting — pathetic one minute and threatening the next. Staggering about while trying to scrape together enough cash to buy a dime bag of coke, he reconnects with Nathan, who has gotten clean and has found shelter in an unusual — probably opportunistic — arrangement. Somehow, through his haze, Mike seems to realize this is not the kind of solution he wants.

In the final stretch, Dickinson shifts into a woozy state that clearly mirrors what’s going on in Mike’s head as visions of the enigmatic woman become more frequent, along with other, more unsettling fantasies that build to an emotionally resonant final image.

Urchin would be nothing without a gifted, vanity-free actor (the lead is the son of Stephen Dillane) who has clearly dug deep into the milieu of addiction and homelessness and is willing to go anywhere the script takes his character — from rapturous highs to desperate lows and all their consequent indignities. Dickinson and Northam make strong impressions in their secondary roles, as do several other actors who almost seem to have been plucked off the streets. But this is fundamentally a one-person show, piloted by Frank Dillane like a reckless driver forever losing control of the wheel.

The other key collaborator is cinematographer Josée Deshaies (Passages, The Beast), who shuffles between intimate shots and wider frames, her camera jostled among the sea of people in the city or composed in its gaze, with minimal movement. The visual textures as much as Dillane’s performance contribute to making the movie feel at all times in the moment.

Since his big-screen breakthrough in Eliza Hittman’s Beach Rats, Dickinson (who’s not yet 30) has mostly skipped the standard pretty-boy route of rom-coms and action hero vehicles in favor of working with idiosyncratic directors like Joanna Hogg, Ruben Östlund, Sean Durkin, Halina Reijn and Steve McQueen. (He’s slated to play John Lennon in Sam Mendes’ tetralogy of Beatles movies.)

Those shoots appear to have functioned as an informal film school, equipping him to tackle a much-trafficked subject in ways that are thoughtful, distinctive and clearly culled from close study of a highly specific world.