Quentin Tarantino’s exploitation black-comedy thriller Once Upon a Time … in Hollywood finds a pulp-fictionally redemptive take on the Manson nightmare in late-60s California: a B-movie loser’s state of grace.



It’s shocking, gripping, dazzlingly shot in the celluloid-primary colours of sky blue and sunset gold: colours with the warmth that Mama Cass sang about. The Los Angeles of 1969 is recovered with all Tarantino’s habitual intensity and delirious, hysterical connoisseurship of pop culture detail. But there’s something new here: not just erotic cinephilia, but TV-philia, an intense awareness of the small screen background to everyone’s lives. Opinions are going to divide about this film’s startling and spectacularly provocative ending, which Tarantino is concerned to keep secret and which I have no intention of revealing here. But certainly any ostensible error of taste is nothing like, say, those in the much admired Inglourious Basterds. And maybe worrying about taste is to miss the point of this bizarre Jacobean horror fantasy.



Quite simply, I just defy anyone with red blood in their veins not to respond to the crazy bravura of Tarantino’s film-making, not to be bounced around the auditorium at the moment-by-moment enjoyment that this movie delivers – and conversely, of course, to shudder at the horror and cruelty and its hallucinatory aftermath.



Our first non-hero is Rick Dalton, played by Leonardo DiCaprio, a failing cowboy actor and alcoholic going to seed in the autumn of his career and in moments of bad temper beginning to resemble Jack Black. His best friend – pathetically, his only friend – is Cliff Booth, played by Brad Pitt in his Ocean’s-Eleven mode of easygoing competence and imperturbability. Cliff is Rick’s stunt double and has an awful secret in his life: a grisly event for which he may or may not be guilty. Cliff has to drive Rick everywhere because he has lost his licence, and he is Rick’s best pal, assistant, factotum, and the person who has to straighten Rick when he bursts into boozy tears of self-pity.

Things head south for Rick and Cliff’s careers when Rick’s western TV show Bounty Law is cancelled. His agent Marvin Schwarz (an uproarious cameo for Al Pacino) tries persuading Rick to head out to Italy to reinvent himself in these new “spaghetti westerns” they have out there. But in the interim and on the basis of Rick’s boisterous turn on an episode of FBI, Schwarz gets him a job on a western TV show in America, Lancer, with Sam Wanamaker directing, and Rick has a weird epiphany. Apart from everything else, he is inspired by the fact that he lives next door to Sharon Tate (Margot Robbie) and Roman Polanski (Rafal Zawierucha), of whom he is entirely in awe.

In tandem with the eerie resurgence of Rick’s self-worth, Cliff finds himself giving a lift to a hippie girl out to the Spahn Ranch, that actual movie location which Tarantino imagines to be the place where Cliff and Rick shot films together and which was, of course, the real-life chilling headquarters of the Charles Manson cult. Cliff makes an impassive appearance at this creepy compound and Tarantino audaciously makes this a kind of western-thriller episode, as Cliff makes a social call on the owner, George Spahn (Bruce Dern). Lena Dunham plays one of the acolytes, incidentally, casting which may be a subliminal reminder of the title both of Dunham’s famed TV show Girls, and Emma Cline’s novel about Manson’s followers.



Rick and Cliff are basically nonentities, the only difference being that easy-going Cliff has no ego to bruise, no ambition to nurse. But their marginal status is transformed by Tarantino’s parallel-universe comedy.



The mention of Polanski and Tate raises the stakes in all sorts of ways: Cliff is offered a blowjob by one of the girls and turns it down because she can’t produce evidence that she is 18. Rick finds himself opening his heart to a preternaturally intelligent child actress (Julia Butters) because he feels that he is over the hill. On hearing that she is eight years old, he mutters that in 15 years time she will know how he feels: a nasty ungallantry of which he is immediately ashamed. All this is a gesture of self-consciousness, a deadpan incitement – and there is no doubt that this is a very male movie, although Margot Robbie gives a sympathetic portrayal of Tate, Dakota Fanning is intimidatingly sinister as the Mansonite called Squeaky and Lorenza Izzo has a spirited turn as the mercurial Italian screen star Francesca Capucci.



The most outrageous scene – and the funniest – is Cliff getting a stunt-man job on The Green Hornet and getting challenged to a fight by Bruce Lee in his Kato costume. It is an extraordinary punch-up, though I’m not sure I agree with how Tarantino imagines the result; but I carried on laughing for about three minutes after the scene ended.



And then we get the finale, a piece of bloody mayhem which leads to a bizarre denouement which might well have you replaying the entire film in your head. It’s entirely outrageous, disorientating, irresponsible, and also brilliant.

•Once Upon a Time … in Hollywood screened at the Cannes film festival, and is due for release on 26 July in the US, 14 August in the UK and 15 August in Australia.

• This article was amended on 20 August 2019 because Lorenza Izzo plays Francesca Capucci, not Francesca Cappuccino as an earlier version said.