Book Of A Lifetime: Lucie Duff Gordon: A Passage to Egypt, By Katherine FrankLetters from Egyp, By Lucie Duff Gordon

I'm not a reader who returns to books; the pressure of unread books bears down on me too heavily. I re-read The Great Gatsby from time to time, when I need to be reminded of how to say as much as possible in very few pages. But while writing my new novel, The Mistress of Nothing, I returned to two books so often that they are both now so tattered and annotated and stuck-up with Post-its that they are almost art objects.

I read Katherine Frank's biography, Lucie Duff Gordon: a passage to Egypt, for the first time when it came out in paperback in 1995; it was recommended by a friend who knew Frank.

On the whole, I'm not attracted to biography as a genre, especially biographies of writers; I'd rather read the writer's work. If that makes me sound rather worthy, I am not – it's the aforementioned pressure of unread books coming into play.

Frank's biography, which I loved, told the story of Lady Duff Gordon's life from beginning to end.

But a single paragraph, describing an incident in Egypt where Lucie lived with her maid Sally, came to dominate my life for the next 14 years.

It read: "A dark, moonless night, and not a soul awake on the boat, or so Lucie thought until around midnight she heard strange, half-stifled noises coming from Sally's cabin next door. Then Sally suddenly called out for Lucie to come to her; she was in labour and needed a midwife."

Sally had concealed both her affair with their Egyptian dragoman, Omar, and her pregnancy from Lucie; after that night on the Nile, things went from bad to worse.

Writing a novel is never easy, but taking nearly 14 years to get this one right is a little embarrassing. I abandoned it completely several times. At one point I spent an entire year writing and researching the book: I produced a single page. It was a good page, but even so, I knew it was time to give up again.

And yet, the story wouldn't leave me alone. I returned to Frank's biography over and over again, scouring the photographs Frank had included for clues; I read Duff Gordon's own Letters from Egypt (a book in print almost continuously from when it came out in 1865) from front to back and back to front.

I spent hours on further research in the British Library. But for me the real story turned out to be the unrecorded story of Lucie's maid, Sally, and the doomed romance she embarked upon in the dry heat of Luxor where Victorian notions of propriety no longer seemed relevant.

This story wasn't told in the pages of any of these books. I had to make that up.

Kate Pullinger's novel 'The Mistress of Nothing' is published by Serpent's Tail