Andrew Miller's novel Pure won the 2011 Costa Book of the Year Award on Tuesday, beating four other category winners after what the chair of judges described as fierce debate.
The eight-member panel, led by London Evening Standard editor Geordie Greig, was sharply divided between awarding Pure the overall award and Now All Roads Lead to France, an account of the final years of poet Edward Thomas's life.
The latter, the prose debut of poet Matthew Hollis, had been the bookmakers' favourite to walk away with the winner's cheque for 30,000 pounds.
The other shortlisted works were debut novel Tiny Sunbirds Far Away by Christie Watson, The Bees by British poet laureate Carol Ann Duffy and children's book Blood Red Road by Moira Young.
It really was a fierce debate and there was quite bitter dissent and argument, Greig told reporters. The debate was prolonged.
He described Pure, set in 18th century Paris and revolving around the city's oldest cemetery, as a rich and brilliant historical novel.
It's a morality tale which engrosses with its vivid invocation of pre-revolutionary France.
Miller had beaten Booker Prize winner Julian Barnes's The Sense of an Ending to claim the best novel section, itself worth 5,000 pounds.
Greig said the Costa awards were particularly difficult to adjudicate, because they pitted different literary genres against each other, unlike many other major book awards.
It feels like you're comparing bananas and chicken curry, he quipped, adding later that it was akin to a hockey player being judged against a free-style swimmer.
Eventually the decision was put to a vote and the panel backed Pure, although Greig did not detail the number of judges behind each book.
It doesn't make it (the prize) invalid, but it does make it difficult, he said, before defending the award by saying: Anything which promotes books is a good thing.
Since the introduction of the Book of the Year award in 1985, it has been won 10 times by a novel, four times by a debut novel, five times by a biography, seven times by a collection of poetry and once by a children's book.
The 2010 Costa Book of the Year winner was Of Mutability by poet Jo Shapcott.
(Reporting by Mike Collett-White; editing by Patricia Reaney)