What is the author's style in Goldfinger by Ian Fleming?

Ian Fleming was a British writer, and his writing includes several British idioms and expressions. Much of "Goldfinger" takes place in America, however, and Fleming's approximation of American speech may seem exaggerated to native speakers of American English. The straight-speaking Junius Du Pont and the wisecracking gangsters in Goldfinger's crew almost seem like caricatures of American types.