It is an accepted fact that any biographer of Jane Austen has to rely to an uncomfortable degree on surmise. No diaries survive and the 160 letters spared to posterity by Austen’s beloved elder sister Cassandra have long been thought to present a sanitised view of the writer’s short life. There is only one portrait of Austen, that inept and unrevealing sketch by Cassandra, ‘prettified’ later by engravers and printmakers to the point of being almost completely useless. People can’t even be sure of the colour of Austen’s hair: contemporary witnesses contradict each other and the only surviving lock, which might have been expected to settle the matter, is too discoloured by time to bear reliable witness.

The story of Austen’s life is famously uneventful but recent biographers have counteracted the vapid tradition of ‘Divine Jane’ by stressing the dramatic and colourful nature of things going on within her orbit (for instance, her brother Frank’s naval career, her cousin Eliza’s probable relationship to Warren Hastings, the trial