Kingsolver takes a decade to get a taste of Orange

It is an epic story about Mexico, McCarthyism and the intertwined love lives of the firebrand painter Frida Kahlo, her husband Diego Rivera, and Leon Trotsky, that took Barbara Kingsolver nearly a decade to write.

Last night, the American writer was rewarded for her nine-year literary endeavour after being given the Orange prize for fiction.

As one of the most respected authors on the shortlist, it was revealed to The Independent that Kingsolver's sixth novel, The Lacuna, was among two other hot favourites – Hilary Mantel's Booker prize winner Wolf Hall and Lorrie Moore's A Gate at the Stairs – which also took a decade of literary gestation to come to fruition.

Daisy Goodwin, the chair of this year's judging panel, said choosing between the three favourite books from the six-strong shortlist was as agonising a decision as "choosing between your three beautiful daughters".

She added: "We agonised and in the end, it came down to the fact that some of the judges felt very passionately about Barbara Kingsolver's book."

"We had very different tastes on the panel but in the end we went for passion not compromise. We chose The Lacuna because it is a book of breathtaking scale and shattering moments of poignancy. There were two people in the room that loved Lorrie Moore's book, and the three which were favourites are books I will never forget. They are three novelists at the height of their powers, while the other three are up and coming who have brilliant things to write."

Kingsolver described winning as a "lovely shock". With the bronze statuette in her hands, the author said: "I have to tell you, in my heart I do not believe that beautiful works of art can be ranked. I'm so proud to be on this shortlist. I believe every author on the shortlist deserves the prize." But she added: "I will take it home though."

The Duchess of Cornwall was set to present the author with the £30,000 prize at last night's ceremony at the Royal Festival Hall, in London. Kingsolver was born in 1955 and grew up in eastern Kentucky. Over the past two decades, she has been extraordinarily successful: she has been shortlisted for the Pulitzer prize and all her novels since 1993 have made The New York Times bestseller list.

Jonathan Ruppin, from Foyles bookshop, revealed that Kingsolver's book was "by far the bestselling title on the shortlist", adding that it was an ambitious novel whose substance British novelists could do well to emulate. "It's a daunting read, which fans of her previous novel, The Poisonwood Bible, won't all take to, but it rewards patient reading. It would be good to see more British writers and more women coming up with fiction as ambitious as this."

The Lacuna is set largely in a series of provincial households in Mexico in which its narrator, Harrison Shepherd – a writer of historical potboilers – grows up with his beautiful mother, Salomé, who always finds her rich men-friends on the losing side of the Mexican Revolution. As an adult, Shepherd joins the artistic household of Kahlo and Rivera, where he meets Trotsky in exile, and is accused of criminal "communist" tendencies in McCarthyist Carolina.