ONCE again, a new film by Lynne Ramsay has been a long time coming. And once again its arrival reminds us what a formidable filmmaker she is, one who turns provocative subject matter into thrilling cinema.

Adapted from the novel by Jonathan Ames, You Were Never Really Here is a painstakingly intense portrait of a decent man knee-deep in depravity and despair. It’s centred on another extraordinary performance by Joaquin Phoenix, around whom Ramsay orchestrates her drama with a hard-boiled but artful direction that brings to mind the likes of Martin Scorsese, Michael Mann and David Fincher.

Ramsay seems less interested in criminal psychology than that of the victims or bystanders of crime. In her previous, We Need To Talk About Kevin, she explored the fall-out of a high school massacre on the young killer’s mother, struggling to come to terms with the fact that she’s raised a monster. Here, paedophiles and sex traffickers are only sketched into the background; the focus is on the person who’s trying to stop them, but is tarnished himself in the process.

Phoenix plays Joe, a former soldier and FBI agent who now has a very particular occupation, as a rescuer of young girls from the clutches of the sex trade. A colleague, McCreary, takes the commissions, then Joe carries them out, working alone and using whatever violence is necessary. “McCleary says you’re brutal,” suggests one client. “I can be,” the reply that barely covers the harm caused by his ball hammer.

But violence is aimed only at abusers and their henchmen. At home, Joe patiently and tenderly cares for his elderly mother. He appears to have no other life, a loner tormented by troubled memories from childhood, and weighed down by the human suffering that he’s witnessed as an adult. It’s a dire existence, which plummets even further south when an assignment, to free a senator’s daughter from a sex ring, goes horribly awry.

Phoenix has an innate strangeness and brooding intensity that are well-suited to playing psychologically damaged men, whether the mad emperor Commodus in Gladiator or the WWII vet Freddie Quell in The Master. He’s beefed himself up here, and with long, pony-tailed hair and a bushy beard gives Joe a hulking, bull-like presence. This is the kind of man who walks in such a deliberate, insulated, intimidating manner that he might as well be invisible.

Working from her own, minimalist script, Ramsay’s attention never strays from Joe – whether her camera is close up on his features or following behind as he marches about his business, or she’s using dream-like combinations of sound and image to convey his tortured psyche. Radiohead’s Jonny Greenwood, who also scored We Need To Talk About Kevin, offers an omnipresent, urgent undertow to the action – sometimes electronic, sometimes strident strings – that adds to the film’s edge-of-seat intensity.

A central scene in which Joe’s assault on the sex ring is observed on black and white surveillance cameras is a tour-de-force representation of real-life horror. It’s one of numerous sequences that bring to mind Scorsese’s classic urban nightmare, Taxi Driver. Ramsay’s work does not suffer by comparison.

Like De Niro’s Travis Bickle in that film, Joe is a traumatised war veteran who finds redemption in saving a girl from the sex trade. Then, it was Jodie Foster’s adolescent prostitute; here, as the senator’s daughter, promising newcomer Ekhaterina Samsonov lends her character a rock-steady gaze and ethereal stillness that could be masking unspeakable suffering, but may also denote an ability to move on. And with that, she lends a bleak business just a little bit of hope.