We don’t get to see every one of the fractured people tucked away in Kevin’s mind, but the ones we do meet include overbearing mother figure, Patricia; Hedwig, a nine-year-old kid who likes hip-hop; and Dennis, a chap who leers through huge spectacles like his namesake, Dennis Nilsen. In his best movies, Shyamalan excels at taking an existing genre and pushing it slightly out of square, so that a supernatural chiller becomes a moving portrait of a psychologist and his young patient (The Sixth Sense), or a drama about survivor’s guilt flips over into superhero territory (Unbreakable). Not everyone was necessarily convinced by The Visit, but for this writer, its fusion of horror, fairytale trappings and pitch-dark humour worked better than anything Shyamalan’s made in years. In terms of style, he’s pulled off the same trick again in Split; he riffs on Hitchcock camera moves and story beats a bit like Brian De Palma used to in the 70s and 80s – and, indeed, there are vague similarities between Split and De Palma’s less celebrated thriller, Raising Cain. While Split is sharp in stylistic terms, it feels somewhat less certain tonally; in certain stretches it toys with straight slasher-horror, before slipping uncomfortably into grisly humour and then back again with something of a lurch. McAvoy evidently relishes the chance to play so many roles in one film, but the result sometimes look more like an impressionist running through his routine of famous voices than a real, desperately ill human being. And this latter aspect might be Split’s stickier aspect; Shyamalan makes concerted efforts to present Kevin as a relatable character rather than a stock villain – not unlike Michael Powell’s handling of the killer in his once infamous (and since rehabilitated, at least in the eyes of critics) Peeping Tom. The unqualified success of Split, I’d argue, is Anya Taylor-Joy. She was magnificent in The Witch, and she’s superb here: believably smart, courageous and thoroughly magnetic. In fact, I can’t help wondering whether Split might have been a better film had the lead role gone to Taylor-Joy, playing a female maniac who keeps teenage men locked up in her basement. Certainly, it might have helped Shyamalan side-step some of the more unseemly moments here, such as his characters’ tendency to shed their clothes as the story wears on. In its most effective moments, Split is a decent genre mash-up. At the same time, it’s also a bit of a muddle: who’s it aimed at? Horror fans will find it all a bit tame; those hoping for an intelligent thriller in the mould of, say, Manhunter or Silence Of The Lambs might be dismayed at all the pseudo-science and teenagers flapping about in skimpy bras. Split is out in UK cinemas on the 20th January.