Unpublished Winterson novel found at Tube station

An unpublished novel by Jeanette Winterson has been found at an Underground station in south London.

The Stone Gods is not due to be published until September. Martha Oster, 27, said she was "amazed" to find the 134-page manuscript lying on a bench at Balham station late on Wednesday night. Winterson's novel Oranges Are Not The Only Fruit won the Whitbread Prize in 1985.

Simon Prosser, the publishing director of Penguin, said it was left at the station by a company employee. Mr Prosser said the incident was "terribly unfortunate," but added it was simply human error. "She went back to the station to try and retrieve it, spoke to the cleaners, but could not find it anywhere," he said.

Ms Oster, a teacher from Tooting, south London, was returning from a night out with colleagues when she spotted the manuscript. She said: "I'm nosy so I picked it up, had a flick through, and realised what it was. I was amazed to find it like that."

She said she recognised Winterson's name immediately. "I studied Oranges Are Not The Only Fruit for A-level and I have a couple of her books. She is one of my favourite authors."

Caroline Michel, Winterson's agent, and managing director of the William Morris agency, said the author was out of the country and not aware of the incident. She said she had been assured by Penguin that it would not happen again. "It is not something that happens every day, thank goodness," she added.

Winterson, 45, wrote the controversial Oranges Are Not The Only Fruit, about a lesbian girl who grows up in a religious community, when she was 23. It was dramatised for the BBC.

Her other novels include The Passion, Sexing The Cherry, Written On The Body, The Powerbook and Lighthousekeeping. Her books for children include The King of Capri and Tanglewreck.

The author, who has also opened a shop, Verde's, in Spitalfields which sells organic food, was appointed OBE in 2006 for her services to literature.