After what is described as a "frantic" phone auction John Murray publishers finally bagged The Meaning Of Night on Friday.
Although the precise details of his book deal are confidential, it is understood Mr Cox's one-book deal easily eclipses, for instance, the approximately £350,000 deal given to Zadie Smith for her first two novels.
Joel Rickett, deputy editor of industry bible The Bookseller, told the Standard: "For the right thing publishers will pay big bucks. Auctions create huge excitement, and if the publishers think they have found something fresh they will rush to get it."
He added: "If you get something out there that stays at the top of the bestseller charts it will earn its publishers back even a huge advance like this."