A WOMAN sat in the corner of the busy cafe, pen in one hand, espresso in the other and baby in a pram by her side. Around her plates clattered, waiters tripped backwards and forwards in their starched white aprons and the customers chattered over pains au chocolat.

The woman didn't seem to notice the chaos in the large wooden-floored space. She was writing a children's book and the only place she could find which was warm - and for the price of a 90p espresso would let her sit quietly all day - was Nicolson's cafe on Edinburgh's South Bridge.

When children's author Joanne Rowling recalls her darkest days, there is a shiver in her voice. But the poverty, the depression and the clammy chill of her one-bedroomed Edinburgh flat where the single mother who had fallen on hard times sought to keep her baby daughter warm, pall in comparison to the looming loss of her identity.

"The feeling of who I was badly damaged by suddenly finding myself a single parent on benefits," says Rowling. "So I wrote to protect my sanity. I have always written and so it was a way of continuing to be me, despite all the ghastly circumstances."

There is no romance to the starving-artist-in-a-garret existence at the best of times. With a baby to feed and clothe and fret over, it possibly constitutes the worst of times. "There were times when Jessica ate and I didn't. I feel like it's a case of 'cue the Hovis music' when I say that, but it's true, however it sounds. When I fetched up in Edinburgh I was pretty much penniless and it was a complete shock to my system."

Her marriage to a Portuguese TV journalist had disintegrated when their daughter Jessica was just three and a half months old and she had moved to Edinburgh to be with her sister.

Rowling, 32, has just picked up a prestigious literary award, the Nestle Smarties Book Prize, for her children's book Harry Potter and the Philosopher's Stone. It is the latest success in a string of events which have seen her rocketed into the league of high-earning professionals, with rival companies bidding for the film rights and a massive six-figure advance.

The story behind the book's genesis however, reads like the plot of a mini-series: impoverished single mother clutching newborn baby wanders through the dreich wintry streets of Edinburgh in search of a warm place to escape her seedy flat. Nursing a single cup of coffee, she sits in a cafe for hours, and, as her baby daughter sleeps, in laborious long-hand she feverishly writes a children's story about a lonely little boy, Harry Potter, who escapes his Dickensian misery by becoming a wizard. The magic is catching. When she sends off the manuscript, to an agent, it is admittedly more in hope than expectation, but a fairytale ending is in store: a $100,000 US publishing deal for the first of seven books, and four companies, two of them Hollywood studios - tussling for the movie rights.

Yet if this rags-to-riches tale of real-life smacks, unavoidably, of cliche, the resulting fiction has been hailed as inventive story-telling at its best. Potter, a little orphan boy, is persecuted by his nagging relatives until at 11 he boards the train for Hogwarts School of Wizardry and Witchcraft, after which his life will never the same again. The same can justifiably be said about Rowling herself. Still based in Edinburgh, the city she "instantly fell in love with", her living conditions are a far cry from her first dank city-centre flat. But her experience of the rough end of life has been a salutary one and she remembers the little kindnesses rendered to her in times of need.

"It is an escapist book and by writing it I was escaping into it. I would go to Nicolson's cafe, because the staff were so nice and so patient there and allowed me to order one espresso and sit there for hours, writing until Jessica woke up. You can get a hell of a lot of writing done in two hours if you know that's the only chance you are going to get."

For its part, the cafe staff was quite happy to let inspiration take its course. "We all know Joanne and Jessica," says general manager Roland Thomson. "They would come in almost every day, and the wee girl would sleep while her mother wrote. It was really sweet."

Rowling says her sympathies go out to single parents in a similar position, while acknowledging that her good fortune is not the kind of thing everyone in the poverty-trap can realistically emulate. "When Harry Potter was published there seemed to be an aura of amazement that a single mother could produce anything worthwhile, which is pretty offensive. I would hope that other women would see what I've done as inspirational, but on the other hand I know I was very lucky. I had a 'saleable talent', to put it crudely, and I also had an education, so even if I hadn't written the book I would have had the raw materials to rebuild my life."

Rowling grew up in Chepstow, Gwent, the daughter of a manager at Rolls-Royce. Academically-minded, she applied herself at her comprehensive school before taking a degree in French and the classics at Exeter. She later worked for Amnesty International in London, and moved to Manchester before a combination of "itchy feet" and a desire to work as a teacher prompted her to move to Portugal. She took a job teaching English and met and married a Portuguese television journalist. In 1993 the couple had a daughter, Jessica, but she was not yet four months old when the pair split up and Rowling headed to Edinburgh to stay with her sister, Di, 30, a law student, intending to leave early in the New Year.

Rowling refuses to discuss her husband, from whom she is now divorced, but says that after separating from him, she had to go back to Britain quot;I had never expected to be in that situation and the simple fact was that leaving my Portuguese husband meant leaving the country where I had set up home and the teaching career I had made for myself. My sister was in Edinburgh, but I had no friends. When I first arrived I was so completely lonely."

Rowling began writing, and then did part-time secretarial work. After 18 months she re-trained as a teacher, and worked part-time at Leith Academy. An $8,000 Scottish Arts Council grant came just when she needed it most, and enabled her to buy a word processor and spend more time on her second Harry Potter book, which is due for publication next year.

"I had been writing about Harry for about four years before I came to Edinburgh and I suppose I had faith in the idea because I had been working on it for so long, but my hopes only went as far as getting it published. The whole thing has completely overshot my expectations."

It also surpassed the expectations of the book world. That Rowling secured such a substantial advance for a children's book was a major event. As a first-time author, John Grisham received $70,000 for The Firm. This year's Booker prizewinner, Arundhati Roy, was advanced $150,000 for The God of Small Things.

But Harry Potter, predicted by some to become a classic in the mould of Roald Dahl's Charlie and the Chocolate Factory, struck a chord in the industry. Aimed at the over-eights, its fantasy has such appeal because the characterisation is rooted in reality. Harry is immensely likeable: kind but not wet, competitive but always compassionate. The novel has already sold 30,000 copies in Britain alone and is being translated for the European market and future American sales will doubtless be huge. Fortunately the prospect of a series of books holds no fears.

"Because I have had so many ideas down through the years, and planned on a seven-book series, the novel plots are already there," says Rowling, who adds that although she is totally delighted with her new prize and the ringing endorsement from young readers it represents - the panel is made up of youngsters - her most exciting moment was when she learned her book was going to be published. "The purest, most unalloyed joy was when I finally knew it was going to be a book, a real book you could see sitting on the shelf of a bookshop."

The staff at Nicolson's make no secret of their pride at Rowling's success. She is still one of their most regular customers, but in one respect at least fame has changed her: now she can afford to eat lunch.

Copyright 1997 The Scotsman Publications Ltd.