When we meet the morning after the announcement of this year’s Booker prize, David Szalay, the winner, seems an extremely genial and gentle author to have created one of the most morally ambiguous characters in recent contemporary fiction. His sixth novel, Flesh, about the rise and fall of a Hungarian immigrant to the UK, is unlike anything you have read before.

Szalay (pronounced “Sol-oy”) is often described as “Hungarian-British”, but that has offended Canadians this morning, he says. His mother was Canadian and he was born in that country, where his Hungarian father had moved a few years earlier. “I’m arguably more Canadian than Hungarian.” Now 51, he grew up in England, graduated from Oxford University, and lived in Hungary for 15 years. To make things more confusing, he is over from Vienna, where he now lives with his wife and young son Jonathan.

For many years, Szalay has been critically acclaimed as “a writers’ writer”. In 2013 he was named one of Granta’s Best of Young British Novelists. There was always a sense that he deserved to be better known. In the past 12 months, he has had a baby and won the Booker prize. “It’s not a year I’m gonna forget,” he says, his voice scratchy from lack of sleep and all the talking he’s already had to do this morning.

Last night was not his first experience of the agonising Booker ceremony. In 2016 he was shortlisted for All That Man Is, an interlinked collection of nine stories about men of different ages, from all over Europe, which provoked controversy as to whether it counted as a novel. It was a “very, very stressful evening” he says. This time he decided “to sort of hypnotise” himself into believing that he hadn’t won. “I maybe succeeded almost too well,” he says. “I was eerily calm – and then when it did indeed happen, I was slightly shocked.”

Flesh was born of the failure of a novel he had been working on for four years. Partly this was due to the pressure of the attention that All That Man Is had received. Also: “the central concept was wrong.” Szalay had written 100,000 words before finally abandoning it. “There was an enormous feeling of relief, as well as trepidation that I now had to start with something else,” he says. “To abandon two books in quick succession would start to seem terminal.”

He wanted to write a novel that straddled England and Hungary, to reflect his feelings of being “emotionally marooned between the two countries”. He also wanted to write about “the physicality of existence”, he says. “Obviously, it’s part of every story, but it’s very rarely prominent as an idea.” He opened a new Word document and gave it the working title Flesh. The title seemed very “unliterary”, he says, and it made his editor nervous. But in the end, they all agreed it suited the pervasive unease of the novel and its central preoccupation – the body.

The unforgettable opening chapter came first, almost as a short story. Fifteen-year-old István is living in a new town on a Hungarian estate with his single mother. A 42-year-old neighbour seduces him and an altercation with her husband ends in disaster. “I would certainly read the second chapter,” Szalay says. “So I then thought, ‘How can we move this on?’”

Move on it does, at speed. István spends time in a juvenile detention centre, then as part of the Hungarian army in the Iraq war. Both these experiences happen off stage. The next time we meet him he is working as a doorman for a club in London. He then gets a job as a chauffeur for a preposterously wealthy man. He becomes preposterously wealthy himself. To tell more would be to give too much away. A lot of things happen to István, most of them very bad. “I didn’t want to be a coward. I didn’t want to shirk, or to leave out things that were quite extreme,” he says. “Obviously it’s totally contemporary in its surface, but underneath that, I did conceive it as something akin to a Greek tragedy, in which the hero has to be thoroughly put through the wringer in order to reach his point of catharsis.” The reader is put through the wringer too.

Szalay’s subject, honed over six novels and 15 years, is masculinity: what it means to be a man today, with an inevitable emphasis on sex, violence and money. In 2025, these are not obviously Booker-prize-winning themes. For years, writers were desperate to be anointed “the new Martin Amis”, but now it would be considered slightly shaming. As he said in his speech on Monday, Szalay knew he was writing a risky novel. “One of the risks I was taking was to write about sex from a very specifically male perspective, and to try to do that as honestly as possible.” We see István smoke and have sex. Sometimes he eats. “It’s very difficult, notoriously, to write about sex,” the author says. “I tried to write about it as matter-of-factly as possible.” Sex and anger, he explains, are largely “non-verbal experiences” – and often the most intense challenge for a novelist, as “you have to deal with everything verbally, unless you leave a blank page”.

István himself is almost a blank space on the page. We have no idea what he looks like, although women are all too ready to sleep with him. (This is his curse.) We don’t know what he thinks or why he does things – and neither, it seems, does he. He is a man of few words. Never has “OK” been deployed so often (about 500 times, apparently) or so meaningfully in a work of literary fiction. “It’s one of the main aspects of the characterisation,” Szalay says. “I very specifically didn’t want a character who unpacked themselves for the reader, either reliably or unreliably.” The result is a triumph of relentless exteriority and brutal realism, at once tragic and comic in its banality.

Wary of the novel being “pigeonholed” as just a treatise on men, Szalay edited out most of the overt references to masculinity. “I hope that it’s about much more than that,” he says. “I hope the book is very emotionally impactful – and that only works if it feels very real to the reader.” He succeeds. It is a feat of authorial magic that he manages to make us care so deeply about a protagonist who is so unknowable that at a crucial moment of moral reckoning, we are uncertain how he will behave.

For all the novel’s fixation on the body, István exists in a specific historical moment. Spanning roughly the author’s lifetime, the novel mentions external events, from the Iraq war to migration from eastern Europe to west, and up to the pandemic, to show how our lives are shaped by political and socioeconomic forces beyond our control. “The end of communism, Hungary joining the EU, those two things completely transformed life for Hungarians,” he says. “Brexit will cause very deep changes in the psychology of the UK.”

Szalay is very happy to call himself a European novelist. Having spent most of his writing career in Hungary and now in Austria, he describes himself as a “literary hermit”. He doesn’t really speak German, he says, and isn’t part of any bookish scene. In previous interviews, it is possible to detect his frustration at the sameness of much contemporary fiction. Certainly, he has no time for the traditional form. “That sort of Russian novel that begins with the main character’s grandparents, and slowly works up to their birth about 200 pages in – that’s probably not my favourite sort,” he admits. “I prefer more compressed or concise novels, books that don’t tell you everything.”

It is no surprise to learn that Ernest Hemingway and John Updike were favourites when he was growing up. “Virginia Woolf is an influence, too,” he says. “I read equally as many novels by women as by men.” He is already halfway through his next book, which “partly” involves a female perspective, he says laughing.

He had planned to spend this day in London with his wife. Instead, she is returning to Vienna and their baby while he stays on to talk about masculinity. It is the first time they have left their son with other people (his aunts). “I think this is probably a good moment to do that,” Szalay says. Winning the Booker is surely a good excuse for calling in the babysitters. “I really didn’t know how people were going to take the book,” he says of his win. “I’m proud that it has connected with so many people.”

• Flesh by David Szalay is published by Vintage (£18.99). To support the Guardian, order your copy for £16.14 at guardianbookshop.com. Delivery charges may apply.