Mary Wesley, who has died aged 90, amazed the literary world by having her first novel published when she was 70, in 1983. She went on to write nine more (three of which were filmed for TV), figured regularly in the bestseller lists and was appointed CBE in 1995.
A remarkably good-looking woman, she had a commanding presence and could appear reserved when meeting people she did not know. But she was much less confident than she seemed and she had a wonderful sense of humour.
She often claimed that her novels were not autobiographical, but aspects of her life are reflected in their themes . A typical Wesley heroine is a young woman, damaged by parental dislike or neglect, who ties herself to a conventional man who does not understand her, only to find happiness later with an eccentric, tender lover, who values in her all the qualities no one else has recognised.
The third child of Colonel Harold Mynors Farmar and his wife, Violet, Mary Aline was born at Englefield Green, Windsor Great Park. She grew up hardly knowing her father and believing that her mother preferred her elder sister.
It was assumed that she would never have to work for her living and so she was not sent to school, which added to her isolation. Her beloved nanny was sacked when she was three and her minimal education was left to a series of foreign governesses.
Regretting this, in the 1930s she attended lectures on international politics and anthropology at the London School of Economics (60 years later she was awarded an honorary fellowship there).
She was presented at court, and married Lord Swinfen in 1937. Having given birth to two sons, she had fulfilled her parents' expectations, only to scandalise them when she left her husband. They were divorced in 1945. The second world war, which was to form the background to many of her novels, changed everything for her.
During the War she found work in intelligence. She once told an interviewer that the war years gave her generation a very good time: "an atmosphere of terror and exhilaration and parties, parties, parties".
It was in 1944, dining at the Ritz, that she met Eric Siepmann, the Winchester and Oxford-educated playwright and journalist. Siepmann's father was German and his mother Irish. Her family strongly disapproved.
They lived together until his second wife could be persuaded to divorce him and then married in 1952, settling in Devon. Ten years after their first meeting he wrote in his autobiography, Confessions Of A Nihilist, that she was "somebody whom I really loved, who believed in God and who thought that loving meant what you give and not what you take".
Their years together were so happy that Siepmann's death in 1970 devastated Wesley. She felt as though she had been cut in half, "like a carcass at the butcher's". Siepmann had changed jobs frequently and never accumulated any capital, and his death left her bereft and without an income. Wesley sold her jewellery and knitted for whatever her customers could pay. She had been writing for years but had no confidence in what she produced, in spite of her husband's encouragement, and threw most of it away.
Her first published works, in 1968, were two children's books, and a third followed in 1983. It was only after Siepmann's death that she found her voice.
Then, in Jumping The Queue, she wrote about a woman who could not bear to go on living after her beloved but eccentric husband's death and planned a suicidal picnic.
This quirky, sad and very funny novel was quite unlike anything else that was being published in the early 1980s. Had it not been for the intervention of her friend Antonia White, it might have followed its predecessors into the bin.
Several companies turned down Jumping The Queue on the grounds that there was no interest in "that kind of book", but when her then agent Tessa Sayle sent the book to James Hale of Macmillan, he confounded his rivals. Her work soon found a wide public and was admired by critics.
Much was made of the fact that the novels are full of illicit sex and that the characters are free with the sort of four-letter words that few women of Wesley's age and class would use. Perhaps more interesting, although it was less remarked at the time, is the hate and violence beneath the surface.
Several of her heroines kill, from Mathilda in Jumping The Queue to Sophie, the unloved but deeply lovable child of The Camomile Lawn (1984, and filmed for TV in 1992).
It is the violent expression of long-buried anger and distress, quite as much as the frank sexuality of her heroines, that makes her work so different. Her novels are suffused not only with her humour but also with the emotions she preferred not to discuss, and they are inimitable. A book about the West Country with photographer Kim Sayer, Part Of The Scenery, was published in 2001.
She had two sons by her first marriage and one son by her second.
J Mary Wesley (Mary Aline Mynars Siepmann):born June 24th, 1912; died December 30th, 2002.