It was at school that she met Juliet Peston, Robert Peston’s younger sister. Later, shortly after she studied English at Sussex University, she and Robert became a couple. After Oxford, however, he left to study in Brussels while she remained in London making arts television programmes. Soon she had married Kees Ryninks, a Dutch film maker. In 1985 they had a son, Simon.  Several years later Juliet Peston was riding her bicycle when she was hit by a lorry. Though she eventually recovered, she was critically ill for a period. Siân Busby, whose first marriage had foundered, was a frequent visitor to her old friend in hospital, where she and Robert Peston met again and rekindled their relationship. Their son, Max, was born in 1997 and they married the following year.  Her most notable achievement in film came in 2001, with a two-hour condensation of the 19-hour epic Chinese opera, The Peony Pavilion. She also lectured in film and performing arts at Royal Holloway. But with budgets for serious arts programmes under pressure, she decided on a change of direction, and began writing.  In 2003 she published A Wonderful Little Girl. Described by critics as “compulsively readable”, it told the story of Sarah Jacob, a farmer’s daughter from the village of Llanfihangel-ar-arth, in Welsh-speaking Carmarthenshire. Sarah was 10 when she began to suffer violent fits, after which she stopped eating and devoted herself to reading the Bible.  These symptoms were seized upon by the local vicar as a display of supernatural piety, with the girl apparently finding sustenance in her faith alone. As popular and press interest mounted, a team of doctors began to watch over Sarah day and night. Nine days later she was dead, and for the first time the term anorexia nervosa was used to describe voluntary starvation.  The Cruel Mother followed the next year to equally glowing reviews. Siân Busby was then asked to write one of a series of history books for young people, and chose Boudicca as her subject. It was published in 2006.  It was not long after, in 2007, that Siân Busby – who had never smoked – was diagnosed with lung cancer. Despite years of gruelling operations and treatments, she remained resolutely positive and pursued her research for McNaughten. The result was evident in what reviewers described as a “an intricacy and sentimentality worthy of Dickens; alternating narrators reminiscent of a Brontë; and a satirical eye as sharp as Thackeray’s”.  Though the book’s Victorian subject matter was richly topical (economic depression, an unpopular war in Afghanistan), it was the character of Daniel McNaughten, freighted with mental illness, that had initially interested Siân Busby. McNaughten, possibly a paranoid schizophrenic, shot at the Prime Minister’s private secretary – whom he was thought to have mistaken for Peel. The case made legal history for its establishment of the “McNaughten Rules”, under which a defendant can be absolved of criminal responsibility “if the person did not know what he was doing or did not know what he was doing was wrong”.  Siân Busby was an immensely creative person, who curated exhibitions on subjects ranging from Jewish history (though she was a Methodist) to the history of dance. In her twenties, she had herself been a performer in dance and cabaret. Latterly she enjoyed singing in the London Welsh Chorale, where she was co-chairman. She was also a stalwart of the London Welsh Centre in Gray’s Inn Road, where she was a trustee. At the time of her death, she had almost completed a further novel, A Commonplace Killing, about poverty and casual violence in London’s Holloway shortly after the Second World War.  She is survived by her husband and their son, and by the son of her first marriage.  Siân Busby, born November 19 1960, died September 4 2012
Si&acirc;n Busby, the writer, who has died aged 51, powerfully evoked the society,   streets, sounds and smells of Victorian and post-Victorian Britain; her   constant theme within this literary landscape was mental illness, something   which had affected her own family.