★★★

M. Night Shyamalan is the type of director that critics seem to will to have a ‘welcome return to form’. Having made his name with a string of early-noughties supernatural chiller/thrillers – The Sixth Sense among them – a series of financially successful, but generally panned blockbusters followed. Slashing his budget from After Earth’s $150m to $5m for 2015’s The Visit has seen Shyamalan return to his filmmaking origins and it’s a trend that continues with Split. Yes, it’s another generally welcome return.

Split is, in fact, a literal return to the director’s early work too, taking place, as it does, in the same cinematic universe (good grief, another one…) as Unbreakable. James McAvoy plays Kevin Wendell Crumb, a sufferer of DID (that’s dissociative identity disorder), here: a Jekyll and Hyde type semi-villain with 23 known personalities and a 24th ‘on the move’ – the so-called ‘Beast’. In a triptych mode of split-storytelling, we witness one of Kevin’s forms kidnap three teenagers on their way home and hold them captive, alongside another ‘Kevin’ attending sessions with Betty Buckley’s Dr. Fletcher (‘Is anybody listening? Does anybody care about us?’). A third strand flashbacks to the childhood of Anya Taylor-Joy’s Casey, one of Kevin’s captives, and the unhappy turn of events that formed her sullen, isolated young persona of the present. As with Kevin, trauma has brought out in Casey an entirely shifted personality.

Whilst her classmates, Claire (Haley Lu Richardson) and Marcia (Jessica Sula), attempt daring and cine-friendly escapes from their prison, Casey schemes to play the many faces of Kevin off each other. She befriends ‘Hedwig’ – a lisping nine year-old form – to undermine the grip of ‘Patricia’ and ‘Dennis’ – both of whom worship the coming 24th persona and seek to sacrifice the girls to it.

We do, of course, need to talk about Kevin. McAvoy is explosive here; an electrically charged screen presence. He’s terrifying, sinister and brilliantly funny by equal measure. In a matter of sleight moments, he twists between each performance with a reptilian whip and impressive individuality. Any one of these characters could have starred solo in another of Shyamalan’s back catalogue. There’s a versatility to McAvoy’s performance that fills the frame of every scene; so much so that all those around must raise their game to compare. Buckley is left with rather too much exposition on her shoulders to push through but Taylor-Joy fares better. With her ethereal presence – so brilliantly deployed in The Witch – and wide eyed gaze, Taylor-Joy lies again here somewhere in the channels of a young Winona Ryder, perfectly matched for Shyamalan’s supernaturally broiling plots.

McAvoy’s dominance here is such that he elevates a more generic whole, for Split is a film on readymade genre tracks and is happy to follow them. Cinematographically dark, and scored likewise by West Dylan Thordson, women strip to their panties according to the plot, whilst McAvoy gets to spend a good chunk of the film topless.

Easy thrills are fine but cast potential for a more meaningful exploration of the fascinatingly complex subject matter in a deep and unfortunate shade. Furthermore, yet another depiction of mental illness through the genre of horror will not amuse all. When Dr Fletcher asks Kevin – who may at this point be ‘Dennis’ faking the guise of ‘Brian’ – ‘I’m going to ask again, to whom am I speaking with now?’ her psychology overlaps uncomfortably with the area of a seance.

A welcome return to claustrophobic and grisly character studies, yes, but one lacking sensitivity.

T.S.