Talitha Stevenson: I’ve never met a rich person who was happy

"My ex was very much in that world. He was a banker, a property entrepreneur. We were together for six years and so I have a lot of friends in that world. I feel like I really grew up in it."

Yesterday the author, shortlisted for the Whitbread Prize for her first novel An Empty Room, published her latest book Disappear, which catalogues the rise and fall of hedge fund manager Charlie Bell. He is an arrogant gambler who deals in "audacious amounts" and moves house seven times in five years, playing leapfrog on London's property ladder. His circles are not unlike the ones Stevenson moved in until recently.

What was all that like at its height?

"Private planes to go away to the country for the weekend, landing at people's houses " she laughs. What? People chartering flights from London to the country? "No! They owned the planes. It was insane. There was a point when I said [to my ex], 'I want less'. I felt money was making us unhappy. There comes a point where everyone is seeing the 'things' and not you. I really wasn't meant to be in that world." (I am somewhat disappointed to note her ex-husband had no plane himself.)

Stevenson, 32, is a glamorous, if slightly eccentric, literary type from a bohemian west London background. With her waif figure, huge blue-green eyes and naturally bee-stung lips, she looks like a Pre-Raphaelite Pippi Longstocking.

Her father John, now retired, was a monk turned barrister who loves reciting poetry at parties. When she last visited him he was copying out Italian vocabulary from Dante. An only child (although she has four half-siblings from her parents' other marriages), she was brought up largely by her mother, a teacher, as her parents split up when she was four.

"I had a very literary upbringing or at least one that was ideal for a writer. Until the age of six or seven I thought the Greek gods were real people. My father rewrote chunks of Homer to include me as one of the characters. I was a very lucky little girl." Because of her father's religious background, at the age of six she watched him give the last rites to someone involved in a traffic accident. Soon after, at seven, she wrote her first novel. "It was about a rabbit with a tragic destiny."

She then went off the rails for a while. She attended More House, a Catholic girls' school on Pont Street, Sloane Square, but by the age of nine she began to bunk off. At 10 she took some time out to work as a stable girl while her mother decided what to do with her. She eventually went to an alternative school in Roehampton, based on the teachings of the German educator Friedrich Froebel, who invented the concept of the kindergarten. The school no longer exists.

"It was very Lord of the Flies. Lessons were optional and there was a skateboarding park." At 16 she read Jane Austen's Emma and immediately started writing her own proper novel. Later, she dropped out of her English literature degree at Christchurch College, Oxford, and went to live in Florence where she fell madly in love with a painter. She watched how he worked and learned to do the same with writing, signing a two-book deal with Little, Brown when she moved back to London at the age of 22.

Just before her first novel was nominated for the Whitbread in 2003, legendary agent Andrew Wylie poached her. She sent him her book after they met at the launch party for Yellow Dog by Martin Amis (one of Wylie's authors) and Wylie suggested meeting: "We met in the Oak Room of the Plaza Hotel in New York and he read the first two pages of my second novel right in front of me."

She met her husband Jonty - she is reluctant to identify him any further than his first name - in 2004 at a wedding. A female guest introduced them, mouthing at Stevenson's future husband: "She's for you." She professes that their break-up was friendly - he "loves the book and has been really supportive", helping out with a lot of the financial detail. In reality, you suspect he broke her heart.

In the past six months she's only had two nights in, she says, rather sadly: "It's a phase you go through after a break-up. You need to get to know yourself again. But I've been out too much and I need to spend some time at home. I've done a lot of crying in the last six months too. Writing requires a lot of faith in the world and that is rocked when you split up with someone you love. So I've been restoring my faith in the world."

As the ex-wife of a hedgie, could she please explain exactly what a hedge fund is? No, she grins, that is impossible. "It is like listening to somebody explaining the rules of cricket. And I think they invest in making it sound very complicated."

Her latest book is bizarrely prescient, because she had the idea for it three years ago - before any hint of the financial collapse - and finished writing it over a year ago. "I can't claim to have any financial instincts so it feels very strange." She thinks she picked up on the mood around her and realised it couldn't last. "It was a kind of instinct. I think perhaps you can just tell by the way somebody laughs that there is going to be a breaking point and it might come soon."

So was there a lot of drink and drugs in her circle, as there is in the novel? "Yes. There were people who were really unhappy and those were their ways of coping with it. I have never met a rich person who is happy, and the richer they are, the unhappier they are. There is a huge amount of addiction in the City [to drink and drugs] and sometimes I thought the whole thing was about finding a way to have a drug addiction or an alcohol addiction."

Sometimes it almost felt as if the money was secondary to that. "People were dealing with crazy quantities of money up until three or four years ago. One of our friends struck me as particularly sad - he had the most incredible quantity of money and an awful marriage."

It must have been fun sometimes, though, right? She pauses for a long time. "It was beautiful. It was Great Gatsby-ish. My ex had properties outside London, we travelled all over the world, we had a lavish lifestyle in Portobello. We had a lot of material 'stuff'. Now I just have a suitcase of clothes and books.

"I find it reassuring that nothing that was important about that time was to do with geography or things. I am just the same person without the chandeliers. I don't have an attachment to money or possessions and I've fought hard not to. I fill my life with stuff that leads away from that."

She often felt uncomfortable around the other women in the hedge fund circle. They either worked in fashion or not at all. "They were always much better dressed than me - with French manicures." She can't believe how she resisted but she did not fill wardrobes with designer clothes. "I have a few smart dresses but I take great pleasure in Portobello market and Topshop."

Her bohemian upbringing has served her well, she says, and she seems to have avoided being seduced by the excesses of the good times by training as a psychotherapist, which she started three years ago. She hopes to set up a practice in a couple of years. "I've always just thought I will be OK. And I know how lucky I am to have made a living out of writing."

Away from her novels - and analysing people's minds ("Both jobs feed into each other") - she loves yoga, salsa and Ian McEwan: "When he finds his big plot, he is the master. Although I love Don DeLillo and Raymond Carver too."

Her days are spent writing and she threw out 100,000 words of this latest novel before finishing it. "I have trouble stopping writing. If I left myself unchecked I would be quite happy writing 12 hours a day. It's a passion, it's like being in love. I never understand why some people say, 'Oh, writing is dismal'. To me, it's a love letter to the world. And sometimes that love is unrequited. But then you just write another love letter."

Meanwhile one thing still fascinates Stevenson. What a lot of people don't understand about the global financial crisis is that there were actually very few high-flying casualties of the credit crunch. "When something like this happens, everyone thinks, 'They must be ruined, they must be desperate'." But they all cashed in on the credit crisis. Yes, people lost their jobs - but they all took so many precautions with their investments and their properties."

This is why, a year on, it all seems business as usual, she adds. Because shrewd businesspeople never allow themselves to get burnt.

"I don't think what happened has changed people. It's human nature. I doubt we've learned anything."

Disappear by Talitha Stevenson was published yesterday (Virago, £16.99)