Zadie Smith wins Jewish fiction prize, but critics say her book is just not kosher

Zadie Smith sealed her reputation as the literary empress of multicultural Britain last night when she won the country's leading award for fiction with a Jewish theme.

The 27-year-old writer's second novel, The Autograph Man, triumphed in the fiction section of the £4,000 Jewish Quarterly Wingate literary prize, which celebrates "major works of Jewish interest".

The non-fiction award, also worth £4,000, went to Defying Hitler, the late Sebastian Haffner's acclaimed memoir of growing up in inter-war Germany. Haffner wrote his vivid testament of his nation's slide into barbarism before the Second World War. He died in 1999. The historian and journalist's son Oliver Pretzel discovered the manuscript and decided to publish it.

In The Autograph Man, Smith portrays young characters whose Jewish roots entwine with other strands of London's multicultural tapestry. Alex-Li Tandem, the signature-hunting hero, moves from his obsession with celebrity through encounters with rabbis and a fascination with the Jewish mysticism of the Kabbalah. The novel ends with a Kaddish – the mourning prayer – for Alex-Li's dead father. Reviewing the book for The Independent, Deborah Moggach admired Smith's "glorious concoction", from "our most original and beguiling prose wizard".

Yet the choice of The Autograph Man has divided the Jewish literary world. Sir Jeremy Isaacs, chairman of the prize judges, praised Smith's "entertainingly contemporary tale" of a hero who "swims in the swirl of London's multi-racial mix-and-match, and somehow stays Jewish". Matthew Reisz, editor of the Jewish Quarterly, said: "A lot of people found the Jewish element rather offensive, and felt that she had used the Kabbalah in a rather Madonna-ish, modish way".

The prize panel was itself split. The television and radio producer David Herman, one of the judges, said he regretted Smith's "lack of real interest or engagement" with Jewish themes. "I don't think that one can really take strongly held religious values and traditions, and play around with them in that way," Mr Herman said. Writing in the London Review of Books, James Wood saidthe book's obsession with ethnic detail "seems essentially inauthentic, and marks the novel precisely as one not written by a Jew".