One inspiration for the plot was when the conservatives in government in New Zealand floated the idea of mining in national parks. The idea was howled down – especially by overseas people who wanted to imagine New Zealand as a clean green country, which Catton says wryly has become more and more of a lie over her lifetime. “I wanted to take the idea that was floated and imagine that somebody had seen it as an opportunity.”

Lemoine has made his fortune marketing hi-tech drones, and everybody in the story is constantly spying on everybody else. “I wanted to comment on how we utterly depend on our devices and the screens that mete out this surveillance,” Catton says.

However, Catton is not interested in delivering preachy messages to her readers. Oddly enough she was inspired by Jane Austen, whom she sees as adept at satire, narrative and drama. “I wanted to position characters so they would draw out the maximum drama from each other. They would live and die by their own actions, so a reader would see things would be different if they’d made different choices.”

So her Birnam Wood characters are flawed, petty, competitive, stirred by all too human emotions or led astray by their own righteousness. The nearest thing to a real villain is Lemoine: “I was interested in the cultural worship of psychopaths, how fascinating we find them, how we reward them. He can rationalise the cost of what he’s doing … he’s very funny, seductive, he has charisma. He was a lot of fun to write.”

Catton was born in Canada and grew up in Christchurch with an academic father, a children’s librarian mother and no television in the house. It sounds like the ideal childhood for a writer.

“It was a very book-friendly household,” she says. “I was left to my own devices as a girl, I played imaginary games with my cat, I’m sure I was very dictatorial.” Her mother used to tell her she had a writer’s name; whatever the reason, she’s never known a time when she didn’t want to be a writer.

That ambition led to a master’s degree in creative writing and her debut novel, the prizewinning The Rehearsal, published when she was 22. She was awarded a fellowship to the Iowa Writers’ Workshop, where she began to write The Luminaries. The Booker win changed everything, for better and for worse.

For better, the £50,000 ($87,000) prize money gave her time to wait for an idea for a new book and the opportunity to travel, pre-pandemic, meeting writers and readers in different cultures. For worse: “I found the idea of representing my country to be very fraught. I felt a lot of pressure to say certain things about the country, and no more.”

That feeling came to a head in 2015 after the prime minister and others bagged her for criticising New Zealand’s “neoliberal, profit-obsessed, very shallow, very money-hungry politicians” at the Jaipur Literature Festival. One right-wing broadcaster called her a traitor and an ungrateful “hua”, a Maori word that sounded like something else. Catton says she became depressed and experienced a strange delusion when she felt buildings were going to fall on her.

“It lasted for months,” she says. “If I walked outside any door, I would brace myself for the facade to come down and kill me. It wasn’t until I could give it a name that I realised it was something that was happening in my head.”

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Perhaps it’s partly a legacy of that bruising time that Catton now lives in Cambridge in England, where her husband is studying for a PhD, and has no plans to return to live in New Zealand. She doesn’t believe Jacinda Ardern’s government changed anything significantly.

“Certainly she responded to some of darkest times New Zealand has known with incredible elegance and grace and ways that were iconic and inspiring. But in terms of political change, I’m not sure what I can point to. Inequity is rising in New Zealand at a terrific rate.”

She worries about her generation, who sacrificed more during the pandemic. “People who were wealthy ended up making a profit and people who struggled were struggling more.”

In this environment, people such as her fictional Lemoine are the most dangerous. “Every time you do a Google search or post something online or click the Agree box, your data is being monetised and sold down the line to advertisers and private interests. We are all keeping these people in this position of obscene power and wealth. They can’t be voted out and they are absolutely in a place where they can blackmail governments.”

But she still hopes things can change. “With judicious reforms we could end up reclaiming the Internet.”

Birnam Wood is published by Granta at $32.99 on February 28.

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