20 minutes into its running time, A Useful Ghost gets its American Pie moment: a mother walks in on her son being sucked off by a hoover that’s possessed by a horny, forlorn spirit called Nat. Yet for all its slapstick and bawdiness, A Useful Ghost, the debut feature from the 35-year-old Thai filmmaker Ratchapoom Boonbunchachoke, is a smart, political comedy with philosophical heft and achingly sincere queer romances. At Cannes, it won the Critics’ Week Grand Prix; the LA Times predicted Boonbunchachoke will be the next Yorgos Lanthimos.

“In the first few drafts, the ghost returns in human form,” Boonbunchachoke tells me over Zoom from Bangkok. “I thought it could be an actor with grey paint on their body, but people told me it’d look like a zombie.” At that point, the story already involved dust pollution – both a genuine problem in Thailand, and symbolic of the government’s destruction of monuments celebrating leaders of the 1932 revolution. “It made sense that if someone returned and possessed an electrical appliance, it would be a vacuum cleaner,” says Boonbunchachoke. “For the first few days after getting that idea, I was afraid to tell my producer.”

Defying physics and storytelling rules, A Useful Ghost comprises multiple interweaving arcs that involve the dead returning as cleaning objects. A self-proclaimed “academic ladyboy” (it’s also how Wisarut Homhuan is named in the end credits) notices that his hoover keeps coughing, and so he hires a repairman, Krong (Wanlop Rungkumjad), who explains that it’s haunted by a dead factory worker. The “academic ladyboy” is keen to hear more, not least because he’s aware that a hunky gay guy is mere metres from his bedroom.

In a story within the story, Krong details how an electronics factory was shut down due to employees dying from dust pollution and returning to haunt the building through various machines. The final straw proves to be Tok, one of the employees who died as a result of his work, whose spirit wreaks havoc in the building – an inspector claims “a ghost is less hygienic than a speck of dust”. In contrast, Nat (Davika Hoorne, a Thai celebrity with 18 million Instagram followers) returns as a ghost who wishes to reinstate a relationship with her human partner, March (Witsarut Himmarat). To sway March’s disapproving mother, Suman (Apasiri Nitibhon), the the heir of her late husband’s factory, Nat offers to help rid the building of rebellious ghosts – in other words, a haunted hoover promises to help the oppressor, not the oppressed.

“It’s in Thai culture that ghosts come back for revenge,” says Boonbunchachoke. “I wanted to make it more political. They take revenge as a collective, not for personal reasons.” As the film unfolds, its political underpinnings become more apparent with direct references to the People’s Party Declaration and the 1976 massacre at Thammasat University. “But the film’s not about those two specific incidents,” says the director. “I wanted to talk about the political victims in Thai modern history in general.”

A Useful Ghost has been repeatedly referred to as a cross between John Waters and Apichatpong Weerasethakul. Boonbunchachoke is ambivalent about the references. He admires John Waters but doesn’t see the influence. Weerasethakul is a “Thai master”, but it’s a “bad thing” that he’s namedropped whenever a young Thai filmmaker’s work is reviewed. Boonbunchachoke offers an alternate hook: in preproduction, he instructed his cinematographer and production designer to ensure the film is “both elegantly perverted and perversely elegant”.

It’s in Thai culture that ghosts come back for revenge. I wanted to make it more political. They take revenge as a collective, not for personal reasons

At screenings, then, Boonbunchachoke has taken delight from wrongfooted audiences who walk in expecting a hoover-related sex farce and end up discussing political dissidents as they leave. “It’s been called a Trojan horse,” he says. “I’m aware it’s quite divisive.” At the London Film Festival, where I sat in a sold-out audience, A Useful Ghost proved to be a crowd-pleaser, and its reviews since Cannes have been ecstatic. Weirdly, it doesn’t have UK distribution. After it screens on May 20 as part of Queer East Festival, it might never play a UK cinema again. “We have distribution across Europe. Even Iceland! But not in the UK. I don’t know why.”

Born in Bangkok, Boonbunchachoke made his breakthrough in 2020 with a 30-minute spy-thriller about a transgender sex worker who goes undercover as a cisgender man with a deeper voice. Eschewing commerciality, it was called Red Aninsri; Or, Tiptoeing on the Still Trembling Berlin Wall. On a related note, the director describes to me the popularity in Thailand of ‘Boys Love’, or BL, dramas. “I’m part of the queer community, and I find that there’s a scarcity of representation. BL dramas are everywhere in Thailand. If you turn on the TV, there’s a new BL drama. But it means that gay characters are confined to romantic relationships. I want to see queer characters in other genres. You couldn’t imagine One Battle After Another or Sinners but queer. Krong and Academic Ladyboy could’ve been a straight couple, but I wanted to make them gay. I don’t want to justify my choice. They’re queer. That’s all.”

Boonbunchachoke believes that while Nat and March are a heterosexual couple in human form, their human/hoover dynamic makes them queer. “In Thailand, we have lots of folktales about human and non-human relationships, like a serpent disguised as a woman, or a tiger disguised as a man. They’re queer, because the couple end up separated from the community. [Nat and March’s] human-ghost relationship resembles an LGBT relationship.”

Even the film’s title refers to a gay trope. “Thailand is known for being LGBT-friendly,” says Boonbunchachoke. “But there’s a cliché in Thailand: if you’re the parent of a queer child, you tell them they can be gay as long as you are useful to society. I grew up listening to this saying. I’m fascinated by this conditional love. So it’s a layer of queerness: ‘You can be a ghost as long as you are useful to society.’”

A further metaphor is how young protesters deploy ghosts to publicise how revolutions were possible in the past, and thus regimes can be overthrown in the present and future. Boonbunchachoke wrote the script in 2020 with a sense of optimism. “We had an authoritarian government, and young protesters would weaponise the past to say that an alternative reality was possible – in the same way the establishment would romanticise the past in a way that benefits their status quo. But it’s weird: now we live in a so-called elected government, and society has regressed. When there were protests, they spoke in public about topics that were considered forbidden. They said it out loud! But now the situation has reversed. There are lots of things we can’t talk about in public anymore.”

Before touring the festival circuit with A Useful Ghost, Boonbunchachoke paid his bills by writing TV dramas, a day job that he describes as simply serving a client, not protecting his own storylines. His film work is entirely different. He’s developing his second feature and wants to continue scripting his directorial projects. “Maybe I should pick up a TV writing job again, because I’m running out of money,” he says with a laugh. “I want to establish my identity as a filmmaker. At least the first three films, I want to write myself. After that? Maybe I’ll move to a new phase of my life where I’m like, ‘OK, I want to have lots of money. I’ll make something more commercial.’”

A Useful Ghost screens at Barbican Cinema on May 20 as part of Queer East Festival. Queer East Festival takes place May 1 to June 6 across venues in London. More information can be found at www.queereast.org.uk