Only 160 of Jane Austen's letters survive, the earliest written when she was 20.

The destruction is seen as part of the family's determination to project a specific image of Austen.

Her brother Henry in his biographical note in Persuasion, which was published posthumously, explained that Jane's life was "not by any means a life of event".

This was reinforced in the memoir written by her nephew, James-Edward Austen-Leigh in 1870: "Of events her life was singularly barren: few changes and no great crisis ever broke the smooth current of its course".

Austen scholars and Janeites alike have long speculated what the destroyed letters would have revealed about Jane Austen, the woman and the writer, and what the family has so successfully hidden from history.

In Miss Austen, a work of fiction, Gill Hornby suggests a solution to the mystery.

Miss Austen is Cassandra in 1840, 23 years after the death of her sister, and she is on a mission, visiting the Rectory at Kintbury and Isabella, the niece of Tom Fowle, her fiancé who died while on an expedition to the West Indies in 1797.

Cassandra knows that she and Jane had written many intimate letters to Isabella's mother, Eliza, and Cassandra believes she can find and destroy any evidence that might compromise Jane's reputation.

She sees herself not only as the executor of her sister's estate but also "the keeper of her flame; the protector of her legacy".

As Cassandra searches secretly for the letters, dodging the attention of Isabella's protective servant Dinah, she remembers her life with Jane as dependent spinsters and worries about Isabella and her two sisters, all now single women with little means of support.

In reality, when Cassandra died she left bequests to the Fowle sisters.

Hornby bravely recreates 10 of the letters that Cassandra discovers, however she doesn't attempt Austen's stream-of-consciousness style, nor her wicked wit, both of which are so striking in the surviving letters.

It is generally believed that Cassandra's destruction of the letters was because Jane had made scurrilous remarks about members of the family.

Hornby, however, presents a different answer.

Beyond the romance and intrigue in both the past and the present, there is a serious undertone to Miss Austen, as Hornby explores the plight of women in Regency and early Victorian England, whether to marry and risk the dangers of childbirth or remain spinsters depending on family for financial support.

Hornby is a skilled story-teller and, as a result, Miss Austen is an entertaining and engaging novel, full of characters reminiscent of Austen's own.

But the mystery of the letters remains.