She looks like a film star: red tights, high heels, hair down to here, just off the train from Paris. And yet you find her three flights up in an East End tower block, a flat filled with African prints, photographs, drawings and a baby crying in a neighbour's bedroom.

The mix is typical of Xiaolu Guo. If you had met her at the age of 8, you might have thought “of course that girl will become one of the most successful and fashionable of the new expat Chinese authors”.

She's been on the edge of East and West all her life. She grew up on an island off China, a fishing village with no running water or electricity, where the only reading matter was Mao's little red book. “When I was young I would stand on the beach, hearing political messages broadcast from Taiwan, to leave China. Now, of course, the pull is the other way.”

She's more than 5,000 miles away from all that, but the distance seems farther. In fact, even squashed together on her small sofa, sharing tea and her “daily dose” of Ferrero Rocher chocolate, I feel a long way from Guo. She's stuck, she says, between the siren call of ambition, artistic freedom, Western selfishness, call it what you will; and the sadness that comes with it, the loneliness.

This is her theme. Her first novel in English, A Concise Chinese-English Dictionary for Lovers, was shortlisted for the Orange Prize for its tale of a sassy young Chinese girl arriving in London, quick to fall in love. Her new book, 20 Fragments of a Ravenous Youth, tells of a similar character, Fenfang, who, like the author, left a peasant life at the age of 17 to make it big in Beijing.

Her theme is not just China, she says with wryness, it is bigger than that. It's more about how growing up - whether from naivety, or communism - is isolating. No surprise that her next book and film (she pops out both with disconcerting frequency) are about UFOs and aliens, loosely inspired by China's place in the world.

“The Concise Dictionary was nothing to do with immigrant culture. It was a very personal look at two people trying to understand each other. It's my homage to a certain kind of philosophy, how the difficulty is with others. That problem is profoundly represented by two lovers.”

As a teenager, her father rejected the life dictated by the State. Wanting to become an artist in the Cultural Revolution, he was sentenced to years in the camps for being “bourgeois”. She recently showed his work at a London gallery - he made a killing.

At the same age that her father took his stand, she too exiled herself from village life. The difference is, she says, much of her generation feels her sense of not belonging. Typically they, like her, lived with grandparents while their parents worked and, culturally, feel miles from their elders: “My life feels independent of family. I'm more of a drifter, I don't feel like I'm from anywhere.”

Her case is extreme - she lives between London (which she likes because it's “full of foreigners”), Paris, (where she is taking up a fellowship from the Cannes Film Festival), and Beijing. But she feels part of the phenomenon: “We're the first generation to leave what we know out of choice, not for economic reasons, but to think about following our dreams.”

With millions of young Chinese flocking to Beijing or the West comes rootlessness on a huge scale. In 20 Fragments, American friends tell her that the Chinese are “better at being American than America”. Fenfang tells her Western boyfriend that they don't have a word for “romance” in Chinese: “We say Lo Man, copying the English pronunciation”.

“It was a sarcastic way of showing that she is against this sentimentalism in Chinese culture. Since the Chinese Revolution all those traditional things have been abolished. We live in a completely modern, industrial country, more modern than Tokyo, or New York, without those beautiful Chinese ink pictures.” But her heroines are often “very romantic, very melancholy”. This comes from the pace of change - and loss. Both Fenfang and Beijing are trying to come of age extremely quickly.

“Fenfang is trying to find beauty in an ugly city. Because of that the book becomes quite dark. She's a youthful character, but she has a 60-year-old sorrow. It's from the past... ideology is something very profound that you can't change overnight.”

With her interest in the difficulty of relationships, her work rate and travel schedule, it is no surprise that she is at present single. “I have boyfriends, but I'm alone. My personal life has disappeared, my work is bigger.”

Before I go, she starts to sound optimistic again. It frustrates her that almost the only news British people get about China is about its economic boom, with no sense of people's lives. The Beijing Olympics may help. “For millions of tourists it will be a chance to step into the country, use the shops, eat unfamiliar food, just like us when we come to the West. I'm an old-fashioned humanist. I believe in the power of personal contact.”

20 Fragments of a Ravenous Youth by Xiaolu Guo

Chatto, £12.99; 208pp

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