Hilary Ford on the genesis of Sarnia:

I envisaged a woman of the late nineteenth century marrying into this milieu, finding it unendurable and fleeing back with her child to the more ordinary hazards of London: of that child, given at her christening the ancient Roman name for the island, Sarnia, but reared in ignorance of her paternal background, discovering, after her mother’s death, that she was an heiress, and being bidden back to claim her patrimony. Skulduggery followed naturally.