Johnny Flynn talks his spectacular leading role.

I have an insatiable need to know things. It’s my most annoying compulsion. I like being in on the secret, as even though my love for the written word knows no end, days unfortunately do. If I don’t have time to finish a book or see a film, I’ll read the plot online, seeking out spoilers for some short term satisfaction. I’m a creator’s nightmare, essentially.

After 22 years of ruining art for myself, I finally got my comeuppance with Beast, Michael Pearce’s feature debut out now. Set on the oxymoronic island of Jersey, between manicured lawns in claustrophobic cul-de-sacs and untamed shores, a serial-killer is taking the lives of young women. Climaxing with a question, the feature’s effect in lies its story, rather than just its conclusion, maddeningly hypnotic if like me, you need all the answers.

Part twisted romance, part whodunit tragedy, Beast follows an unlikely pair, brought together by their rejection of the stifling island society. Restrained by a strict family and the shame of a violent childhood secret – having wielded a pair of scissors to a classmate – Moll (played by Jessie Buckley) finds a new life when she’s saved from an assault by the unpolished poacher, Pascal.

Portrayed by Johnny Flynn, Pascal is the prime murder suspect from the get go, what with having a gun and all, not to mention an unexplained sketchy past. Moll hides the story of her attack and saviour from the police at first and it quickly unfolds that while Pascal seems the most likely criminal candidate, he isn’t the only one. A fast-found deep connection from feeling as though they are both outsiders, Pascal and Moll discover the intricacies of each other’s pasts, isolating themselves until the police come knocking, investigating bodies dug up next to potatoes.

“It’s kind of based on a real case in Jersey,” Flynn explains to me on a transatlantic call from New York, where, at the time of talking, he stars in Martin Mcdonagh’s Hangmen. “In the 60s, a guy – ‘the Beast of Jersey’, he was nicknamed in the tabloids – was doing awful things and he was just one of the community, he was just someone that everyone knew.”

There are time-stopping, consuming moments in the film – Moll in a screaming rage that feels cathartic just as a viewer, or hacking away at a golf lawn in furious defiance – but the nuances are just important. The way Hilary (Geraldine James), Moll’s uppity mother and the family cohort try to overlook the chilling mystery in their town and carry on as normal parallels reality, Flynn suggests. “The fact these things happen in small communities and you don’t know who it is is something that Michael drew on,” he explains. “There’s a few dark little corners in Jersey’s past that, because of trying to make it into a holiday destination, are often moved over by more conservative members of the community, trying to make it really seem like everything’s ok.”

Pearce was raised on Jersey and as Flynn puts it, knows the island “intimately”. That knowledge provided a forewarning before they landed to shoot: “Michael said as we flew over there, ‘People are going to be really interested in what we’re doing and if you say we’re making a film about the Beast of Jersey, it’s still very real.’ We’d just say we’re making a fairytale, really.” While that might have been their guise it was certainly no lie, the sense of nature’s tumultuous power and the forces of emotion permeate every scene, whether eruptuous or anxiously still. “It does have the template of an ancient fairy tale, where by we learn through the story,” Flynn elaborates. “It allots a conscious understanding of ourselves.”

In that understanding is a debate over the damnation of individuals for their past. How much repenting is satisfactory? Why is forgiveness so often overlooked as a vital part of rehabilitation from trauma? “I think that’s what’s good about the story…” says Flynn. “So much about our society that I think is wrong is our judgement of good or bad, our need to judge things. You see that really clearly with Moll’s mother, and her family and the way she’s treated there – they think they have her best interests at heart, they think they’re doing the right thing for her – because they think of her as a troubled person, but they’re crushing her. Who judges whether somebody has ticked all the boxes to be a valued member of society again? She had this incident in the past where she stabbed a girl and she’s still living out the penance for that.”

Both the complicit and compulsive deceit surrounding both Moll and Pascal coalesce into a magnetic force between Buckley and Flynn. Moll lies for Pascal, so when it becomes apparent he might be lying to her in return, she can either commit to him blindly or bet against him; succinctly summarised as a headfuck. “It was really amazing working with someone as fearless as Jessie,” says Flynn, when I comment on a particular scene where Moll lets out a guttural scream at a funeral. “I was really passionate about the script and I really wanted to do it. I had a sense that you really had to go all the way with those big scenes… Michael, because it’s his first film, he’s a very precise and exacting person in terms of what he wants and the story he’s trying to tell… It felt a bit like the way you rehearse a play, you go really far into the journey that the scene presents… I think he created that space for us to do that and Jessie and I were really close as well so we had a real trust… We could be vulnerable and tell each other to feel safe, to let it go.”

As considered as every movement and monologue feels in the film, some of its brilliance perhaps lies in the side effects of shooting on location. “A lot of Jersey is small roads and 20 mph limits, there’s no infrastructure for a film crew,” explains Flynn. “The most emotional scene in the film – the bit where we’re on the cliff shouting at each other – there was a tourist bus that arrived with 60 OAPs!” As “60 blue-haired grannies” watched on under order of silence, Buckley and Flynn got a single take. Another scene was forced into a car during a storm due to time constraints, the DIY elements throwing curveballs and resulting in raw performances. “Everyone worked overtime every day and it was really fulfilling and exhilarating… We had to reinvent bits of the film to accommodate for what we had, so there was a real response to the elements in that way,” and grannies.

After an intense five week shoot for Beast and now orbiting the press surrounding its release, Flynn is turning his hand to writing his own scripts and as an accomplished musician, he’s combining the two artforms. “I do quite a lot of composing for different projects… I’m doing a project where I’m writing a children’s musical… We’ve got theatres booked and everything,” he explains the show will arrive at the Rose Theatre in Kingston next year. “I’ve got a bunch of different things in different stage,” he continues. “Definitely into making things from scratch. I’ve been inspired by working with wonderful people, like Michael or Martin McDonagh on this play. I get to work with amazing writers and it’s great to feed off of them.”