“I seem prolific,” she says, in her steady and elegantly articulated voice, “but then I have been writing for a long time. Since I was five, my mother said.” She was 89 this week. First published in 1936, she recently finished the first draft of her latest novel for adults. Meanwhile, this year’s novel for children, Premlata and the Festival of Lights, is now in paperback (Macmillan).

One of the incentives for starting to write so young was that there were no bookshops in the remote little river town in Bengal where she grew up. The First World War made it impossible either to return to England or to have books sent out, and her family was obliged to make its own stories. What she did read was mostly books for grown-ups from the library of the nearest club. “I had a very trusting maiden aunt who would find books she thought were suitable and then mark any passages that weren’t with a cross at the beginning and end. We were honour bound not to read them. My sister,Jon, was very honourable and faithfully observed this. Of course I read the parts between the crosses.”

This experience may go some way to explain why when she is writing she does not think about the difference between child and adult readers. “I just have an idea and it develops. I merely think about the story.” And why many of her books, including, say, The River (1946), The Greengage Summer (1958), and The Peacock Spring (1976) - which were all made into films - sit somewhere between categories, and explore the transition from childhood to teenage years.

She does say, though, that when she tries to alternate writing novels for children and novels for adults, it is “not because I want to relax, because it’s much more difficult to write for children than it is for adults. The discipline is terrific and the younger the child the greater the discipline. You can’t use very many words. You can’t have soliloquies or long descriptions or flashbacks. You have to bring everything into the narrative.” Not all children’s authors observe these limitations. “Which is why so many children’s books don’t work.”

She had the great advantage, as she sees it, of a lack of formal education in her early years. Godden, exiled from Britain by the Great War, did not go to school until she was 12, which helped to make her childhood “halcyon”. When she got to school she was unhappy. She “couldn’t settle” and went to five schools in two years - one of which, a convent, is unfavourably immortalised in the book and film Black Narcissus. Her last school was in Eastbourne, where she had “an enormous piece of luck”. The vice-principal was a dramatist who decided within a week that it was too late to try to teach Godden maths or science, and took her out of classes to teach her only French and literature, individually.

“I thought it would be wonderful. At last somebody would listen to my stories. But for two years I never wrote a single story. I spent the first term reducing the leader of The Times to 14 lines, comparing the use of consonants in ‘L’Allegro’ and ‘Il Penseroso’ to see how they created different moods, writing essays without any adjectives or adverbs, or without using the word ‘I’.” This inspirational teacher made all the difference to Godden’s writing. “I owe her more than I could possibly say. ”

Another influence on her as a writer was her relationship to her elder sister Jon (the model for Joss, the innocent Lolita of The Greengage Summer). “Jon was very, very lovely and I was always in her shadow - which was a very good place for a writer to be. Nobody bothered about me.” It made Rumer an observer. Jon also became a writer - and a painter - and collaborated with Rumer on an autobiographical volume, Two Under the Indian Sun, in 1966. (Rumer wrote two full volumes of autobiography in the late 1980s. ) Jon married a rich man and never had to pursue her writing career with the dedication of financial necessity.

Godden was unhappily married for 12 years to a man she did not love. She had conceived his child and refused to abort it, against the urgings of both her doctor and the father-to-be. In those days (1934) and in those circles, there was no choice. After their divorce, Godden rented a small house and a plot of land in Kashmir where she wrote and grew herbs and brought up her children. She was hard up (her husband had lost their money on the Stock Exchange) but says it was a very happy time. In the winter she saw no Europeans, but was visited by the gypsies moving their sheep down from summer pasture. “I had to work because I was the provider, the breadwinner, not only for my own children but for a great many people. My mother was left very badly off when my father died because he commuted his pension. I had a lot of dependants. ”

Godden’s knowledge of gypsy customs later found its way into The Diddakoi (1972), the story of a gypsy girl who has to find a new life in a hostile society. As she says herself, she has always been a “protester for the underdog”. She carried this attitude to an extreme in the 1930s when she took Eurasian children as pupils in the dancing school she founded in Calcutta. (Dancing was, after writing, her second great love; in England she ran a dancing school, supported by her friend Ninette de Valois, but returned to India at the beginning of the Second World War - in order to reunite her two daughters with their father - and set one up there.)

This was social disaster - not only were dancing schools usually covers for brothels - and therefore “asking for trouble” - but Eurasians were beyond the pale. Godden could teach Indian and European children together,but the Eurasians had to be kept apart. Neither group would countenance them. The cowed existence of the Eurasians also became the subject of a novel, The Lady and the Unicorn (1937).

Since Godden’s Kashmir days she has lived again in England: in Arundel in Sussex, in Highgate in London and in Henry James’s old house in Rye. She had a happy second marriage of 24 years, and since being widowed, moved near her daughters in Scotland, because she thinks “when you

are old you can be a nuisance to your family because once upon a time they were a great nuisance to you. But you must never be a nuisance to your friends.” She now lives largely independently in the converted stables of the home of one daughter (though the other is now distant again,on the Isle of Wight). Besides her two children she has lots of “spares”, including an Indian “stepdaughter” she never formally adopted but brought up, as well as four grandchildren and seven great-grandchildren.

She has returned to India for the setting of her novel in progress and for Premlata, a heartwarmer not unlike The Diddakoi about a poverty-stricken outsider who finds wealthy protectors.

Despite certain recurrent themes, the diversity of setting, subject and audience makes Godden’s books hard to classify. This, she says, “tells against me” because “the British are such puddings. They like you to write the same thing over and over again. ” She sees her writing career like a river: “You let the tide take you and all the life of the river goes on around you.” She quotes her great friend Jean Renoir, who directed The River, saying “People run around looking for ideas. They don’t need to. If they have one idea they can just let it go and it brings in other things and the story evolves.” She does believe, though, that books made with care and thought and time - which for her means writing all her manuscripts by hand - will last, like “hand-made shoes”.

Old age involves a certain simplification for Godden, since she can’t do all she used to: a degree of deafness, for instance, prohibits the theatre- and cinema-going

she once loved. But, she says, “I’ve had a lovely life.” And she still feels the same wonder she felt in her youth. “I don’t think I’ll ever quite grow up.”