A housekeeper finds the body of her multimillionaire boss in the study, his throat slit, a knife having dripped blood all over the white sheepskin rug. “Shit!” she says. It was unlike Agatha Christie to open a novel with a swearword. But this is not one of her books. It’s the first line of Knives Out, the outrageously fun homage to the queen of crime from Rian Johnson, the director of Star Wars: The Last Jedi. Knives Out stars Daniel Craig as a hot Poirot, the world-famous Louisiana private detective Benoit Blanc, hired to investigate the death of bestselling crime writer Harlan Thrombey (Christopher Plummer).

The police believe the case is an open-and-shut suicide; Blanc thinks otherwise. “I suspect foul play,” he says with a hokey deep-fried southern drawl. Was Thrombey killed by a member of his own family? A loathsome bunch; any one of them could be the killer.

Johnson is a man with clout and credibility. Hollywood is presumably rushing to tie his shoelaces after he directed the edgy cool indies Brick and Looper then took on George Lucas’s franchise. Yet in 2018 he spent his downtime between Star Wars episodes writing and directing his love letter to Christie, a novelist hitherto considered to be the purveyor of hot-water-bottle-cosy murder mysteries. Is that traditional view of Chistie dying a death?

Yes, says the Christie biographer Laura Thompson, who believes attitudes have been shifting for a few years. “While I was writing the biography, I can remember going on to Radio 5 and being absolutely ridiculed by a couple of crime writers, naming no names, for writing about this quaint old dear. Now she has become cool, which I would never have predicted when I used to read her in secret.”

Johnson tells me he discovered Christie on the bookshelf at his grandparents’ house. “I was probably 11 or 12 and I’ve never stopped [reading them]. There’s that line they always pull out that next to the Bible, Agatha Christie is the bestselling author of all time. So it’s weird to say she’s under-rated as a writer, but I really think she is.”

There is nothing cosy or antique about her novels, he says. “It’s not like she was an incredibly political or socially conscious writer. But she was engaging with gender roles; there was always the grumpy old colonel scowling at young women smoking cigarettes. She was very much writing to her time. The idea of doing that today felt very exciting.”

And it’s the here-and-nowness that makes Knives Out so entertaining. As the Thrombey clan gather at the family pile in Massachusetts for the reading of the old boy’s will, they bear a striking resemblance to the adult children in HBO’s Succession: the ruthless, spoilt, emotionally stunted offspring of a domineering self-made man. (Christie readers will spot similarities with her novel Crooked House.)

The film could not be more contemporary. This is a family divided – “alt-righters” and cardigan-wearing liberals furiously arguing around the hearth about Mexican migrants locked up in cages on the border. One character speculates that Harlan’s Trump-supporting teenage grandson spends his time “masturbating joylessly to pictures of dead deer”. But truly this is the narcissism of small differences – one Thrombey is as noxiously privileged and entitled as the next.

‘An intrepid, pioneering, passionate woman’ ... Agatha Christie in the 50s. Photograph: Popperfoto/Getty Images

Fans will spy Christie’s fingerprints all over Knives Out. Her obsession with servants is present and correct. Blanc, the last of the gentlemen detectives, puffs on a ridiculously long cigar, a shark’s glint in his eyes. Johnson laughs when I ask him how far he based supersleuth Blanc on Poirot. “He is very drawn on Poirot tropes. To the point where I kept writing all these eccentricities and had to pull back. It was starting to feel like Poirot karaoke. Everything I love about whodunnits I tried to stuff into the movie.”

But Knives Out is not a parody of Christie – unlike the recent Netflix comedy caper Murder Mystery, starring Adam Sandler and Jennifer Aniston as hapless American tourists framed for bumping off an English billionaire. Johnson tells me he enjoyed Murder Mystery. “I’m a whodunnit junkie, I watch them all.” But the film he raves about is Kenneth Branagh’s 2017 film adaptation of Murder on the Orient Express. “I loved it. I came in with my arms crossed because [Peter] Ustinov is my favourite Poirot, but Branagh did a terrific job.”

Branagh defended Christie in an interview with the Observer. “People essentially have her down as a sort of Miss Marple – a sexless, removed, bookish, woolly, very English sort of individual,” he said. “They are not aware of the intrepid, pioneering, passionate woman that she was.”

John Curran, the author of Agatha Christie’s Secret Notebooks, agrees that there is a lot of snobbery about her novels. “People say: ‘Oh her plots are great, but she’s can’t write dialogue or her characters are hopeless.’ I wouldn’t claim that she’s Jane Austen. But that’s not the point. She never claimed to be a good writer. She called herself an entertainer and you couldn’t argue with that.” Christie broke all the rules of murder mysteries, he adds. “She was completely ruthless in her choice of murderer. Just because someone is likable or pleasant or good-looking, you couldn’t depend that they’re not the murderer.”

Thompson points out that Christie’s murderers often got her into hot water with her American publishers; they were appalled by the idea of a 12-year-old girl bumping off her grandfather in one novel. “She’s more of a sophisticate than she’s given credit for, I think,” says Thompson. “In a book like The Hollow, there is not a speck of judgment in her treatment of adultery. The wife is good friends with the mistress. It’s quite shocking really.”

Kenneth Branagh as Hercule Poirot in Murder On The Orient Express . Photograph: 20th Century Fox/Allstar

But why did we all get so sniffy about Christie in the first place? At HarperCollins, her publisher of 25 years, David Brawn believes the 80s generation of darker, psychological crimewriters had something to do with it. So too did the TV adaptations starring Joan Hickson as Miss Marple and David Suchet as Poirot. “Agatha Christie became a TV property rather than a feature-film property. It made her accessible, but it was cosier.”

One woman who has had a lot to do with dusting off Christie’s reputation is Sarah Phelps, the scriptwriter of five BBC adaptations, from And Then There Were None to The ABC Murders. She had to be dragged kicking and screaming to Christie. “I thought it was a cosy little parlour game, something that wouldn’t appeal to me. I was so habituated to Agatha Christie the brand. I was really shocked when I read And Then There Was None. I was reading it thinking: ‘This has got nothing to do with cups of tea.’ This is Aeschylus, utterly remorseless, astonishing and subversive. What’s happened to make these stories so incredibly safe? I think she is beady-eyed and tricky.”

Phelps said she got angry responses to her ABC Murders for emphasising the fact that Poirot is a refugee. “But Christie shines a light on that,” she says indignantly. “Both her detectives are outsiders, they’re strangers. One is a spinster, one is a refugee.”

She adds: “I don’t know why people are so invested in the idea Christie is there to short up their version of themselves. She’s not there to do that. She’s there to scratch a cold nail across the back of your neck.”

Knives Out is released on 29 November