As a young girl Nadine Gordimer was removed by her mother from the convent school where she was one of the few Jewish children. Isolated from her friends, she became, as she puts it, a “little old woman”, mooning around her local public library in Springs, the pioneering goldmining town 30 miles from Johannesburg. Her days were long and lonely. She was a talented mimic and amused herself by impersonating her mother’s friends, and by dreams of becoming a ballet dancer.

So much about South African society confused her. She could not understand why she had to stay at home, or why the black people who worked in the mines did not come to town. “I assumed black children didn’t want to read; my parents didn’t discourage this way of thinking or question why we had a racist Government,” Gordimer says.

Which was baffling: for her parents were part of the Jewish diaspora. Her father, a watchmaker, arrived in South Africa from Latvia, a victim of tsarist pogroms; and her maternal grandparents were East End Jews, who came to the mining town of Kimberley to prospect for diamonds.

But through her reading Gordimer began to understand the harsh absurdity of what was to become apartheid, and to take her first tentative steps as a writer. She found her voice, as Time magazine once said, as the representative of “South Africa’s restless white conscience”, and one of only seven women to receive the Nobel Prize for Literature.

Crouching tinily on a chair in an hotel bedroom in Central London, she is still baffled by her mother’s action. “I don’t understand why she did this strange thing, taking me out of school. There was talk of my having a heart tremor. But I don’t think it was that.

“There are deep psychological reasons why parents cling to their children. It wasn’t that I was an only child (she had a sister who went to school). You see it the other way round with adult men who cannot leave home. They can’t get away from Mummy. And sometimes Mummy can’t let her child go.”

At the age of 74, Gordimer could easily be mistaken for a retired ballet dancer, with her silver hair scraped tightly back into a bun, and delicate, graceful movements. In conversation, she is vigorous, fierce and steely. Small talk is reduced to a polite minimum. Questions of which she does not approve are brushed aside disdainfully. Her response to my opening remark about how she arrived at the central idea of her new novel, The House Gun , is conversation-stoppingly abrupt. “You can’t ask me that; I’ve written 21 books. How your ideas come to you is a very slow, subconscious process.”

Today Gordimer complains of endless demands on her time. A euphemism, perhaps, for this interview. Since becoming a Nobel laureate she has erected a picket fence around her private life. “I will never write an autobiogra phy,” she says, challengingly. “My private life is exactly that: private.”

But it is well known that you read literary biography?

“Yes. But everything I want to reveal about myself is in my books.”

So what do we find in her books? Awarding her the Nobel Prize in 1991, the Swedish Academy of Letters praised the way Gordimer writes “with intense immediacy about the complicated personal and social relationships in her environment”. This willingness to grapple with the complexities of contemporary South Africa is her greatest virtue.

Many of her novels read like parables of the sickness of the apartheid years. There is always tension of a complicated political kind in her work. Her white characters are riven by internal conflict, torn by the desire to live in affluent seclusion, and by the rival claim of social responsibility. Many dream of escaping from South Africa.

But Gordimer never left, even though several of her novels were banned, and many of her friends were imprisoned without trial, tortured and even murdered. Though she never completely lost hope, there were moments of despair. A work like July’s People (1981), about a violent civil war which reduces the leafy white suburbs of Johannesburg to bomb-blackened ruins, is an unmitigated cry of rage.

“There were times when things were so bad,” she recalls. “But a kind of obstinacy made me stay: no matter how awful things became it was part of my inheritance, my destiny. If I’d left I would never have cared so much about what happened.”

Gordimer’s response to being a white South African, to being part of the oppressive minority, was “to throw my lot in with the black majority”. She joined the ANC, and remained a committed member even when the organisation was outlawed. She and her husband, the business man Reinhold Cassirer, sent their two children to school in neighbouring Swaziland, so as to avoid a segregated education. They remain close to Nelson Mandela, Walter Sisulu, Ahmed Kathrada, Govan Mbeki and other graduates of the self-styled Robben Island university.

How true are the stories that Mandela asked Gordimer to co-write his autobiography? “I would never ghost-write anyone’s autobiography,” she says. “But I was called in by Mandela when he was being besieged by publishers after coming out of prison. He said ‘I don’t know what to do, can you help?’ He’s a brilliant politician, but he didn’t know anything about publishing contracts. I was happy to advise him on what to do.”

Did she collect an agent’s fee? “No,” she says, laughing for the first time. “I was flattered to be asked.”

There has been speculation that in post-apartheid South Africa, Gordimer has nothing more to say; that peaceful transition to a new democratic order has deprived her of a defining subject. The House Gun ought to confound any sceptics. It is an absorbing account of the urban violence and tensions of the new country, filtered through the anxieties of a middle-class couple whose son, accused of murdering his former homosexual lover, is being represented by a black lawyer.

“When I won the Nobel Prize I didn’t want it to be seen as a wreath on my grave, as some sort of terminus,” Gordimer says. “I wanted to keep working, to make sense of what was happening around me. The end of apartheid isn’t the end of life; it’s the beginning of everything else.”