There is a moment quite early on in Shame, artist Steve McQueen’s second feature, where Brandon (Michael Fassbender), successful executive and sex junkie, returns to his apartment after another illicit encounter. It appears there’s an intruder – music is clearly audible when he approaches the door. We hear the strains of I Want Your Love (12″ naturally) by Chic, the greatest band of the disco era. Chic’s sophisticated, supple orchestrations and elegant pop sensibilities masked a dark, heavy soul, documenting the fine line between euphoria and the comedown. There’s a heavy price to be paid when you immerse yourself in excess – be it sexual or narcotic – but when you fear rejection sometimes it’s the only way. Nile Rodgers and Bernie Edwards understood this perfectly and – in Shame – so does McQueen and his writing partner Abi Morgan.

At the beginning of the film, Brandon is in the grip of severe carnal cravings. This is a man so incapable of tearing himself away from sex his work’s hard drive has been incapacitated by porn-surfing, and he can barely get through a cup of coffee without taking a toilet break for a one-handed interlude. He’s holding on, just, although his life does have its pleasures. He has a good job, a nice apartment and – being unattached – can enjoy guilt-free trysts with the hotties his pervy married boss singularly fails to connect with. But when his sister, an unemployed club singer (Carey Mulligan), shows up at his apartment his protective casing begins to crack.

The performances in Shame (especially those of Fassbender and Mulligan) are truly naked – metaphorically and physically. Fassbender struts around his apartment nude and preening. Even his reunion moment with his sister takes place with Mulligan totally starkers, having been surprised in the shower after letting herself into his apartment.

There’s a vague suggestion in the film, only a hint, that these two may have collective shame of their own. There’s a frisson to uncomfortable scenes of them arguing and fighting as her flighty ways (rocking up at his apartment, leaving detritus all over his clinically clean abode, having sex with his boss) start to eat away at Brandon. Something bad has happened in their past and is alluded to, but never explored. McQueen and Morgan don’t present this as an excuse or a riddle to be solved. But there’s a feeling that their shame – shared or individual – can’t quite ever be expunged.

Hunger (McQueen’s debut, also with Fassbender) good as it was, felt like an artist making bold steps as a director. Shame feels like the work of a true filmmaker with an artistic sensibility. There’s more fluidity to the camerawork, more space and texture. The film still carries certain affectations and everyone is relentlessly attractive (a three-way fuck is shot like a Terry Richardson photo-shoot) but there’s also a cool distance. Small moments of intimacy, physical and emotional, are captured with grace and an artist’s eye.

There’s a sly comic undercurrent in places too. Near the beginning there’s a DePalma-like moment where Brandon catches the gaze of a pretty girl on the train, and their ‘moment’ becomes super sexually charged. It almost teeters into comic risibility. I wasn’t quite sure whether the implication was that simply by staring at her he had induced her to orgasm (take that, Magneto) or whether it was all in his mind.

Abi Morgan must take good deal of credit here. After taking a fairly sizeable battering for the lack of verisimilitude in her recent TV drama The Hour she is on much surer territory. The dialogue in Shame is as lean as Fassbender’s torso and the exchanges between characters in search of intimacy and connection carry a welcome tang of authenticity.

Carey Mulligan, who I’ve never quite ‘got’ in any previous films, does lovely, understated work. Her character is a heartbreaking smudge of lipstick, peroxide and leopard-print who could’ve ended up a quirky, underwritten nightmare. But Mulligan is tender and real and I loved her softer moments, and that the worse she behaves the more she needs affirmation, confirmation and intimacy. And what a bold actor Fassbender is. He pretty much carries the film, and makes Brandon a flawed, likeable but always frustratingly remote figure. There is something wonderfully graceful about this actor, he never mugs for sympathy. A great career lies ahead.

This isn’t a perfect film. It’s a very serious, bleak work, at times a bit too uptight. I would’ve loved McQueen to loosen up a little more in places, inject a little more light and shade.  There are some truly brilliant scenes with a beautiful co-worker Brandon briefly dates and who brings out hints of the man he could be away from the hookers and online sex chat rooms. And I sometimes wonder why it is always the case that films that deal with sex (especially English and US films) have to associate it with guilt and disdain; something to be purged or paid for in some way.

But then Shame, like its aesthetic bedfellows American Gigolo and Cronenberg’s Crash, isn’t really about sex at all in the end. It’s about much more; addiction, fear of intimacy and the need for – and rejection of – love. Which brings us back to Chic again: ‘Sometime/don’t you feel/like you never really had/a love that’s real?’