A funny quotation from Francis Galton, as given by Nicholas Wright Gillham in A Life of Sir Francis Galton:
America most certainly does not beat us in first-class works of literature, philosophy, or art. The higher kind of books, even of the most modern date, read in America are principally the work of Englishmen. The Americans have an immense amount of the newspaper-article-writer, or of the member-of-congress stamp of ability; but the number of their really eminent authors is more limited even than with us.
(On a more serious note, there has been a very striking shift in mentality in Britain from, say, my grandparents' generation to the generation of readers and writers brought up in the postwar era concerning this question of "English" versus American merit. For Martin Amis and other writers of that vintage, it was almost a necessary part of the rebellion against the English establishment to assert that the exciting work in fiction was being done in America. And I think there's still a certain amount of excitement in the air about American and American-inflected fiction, despite the tarnish the Blair-Bush nexus has left on Anglo-American friendship, literary or otherwise. For my English grandfather, I am sorry to say it was virtually inconceivable that anything very interesting or top-rate should have been going on intellectually in America, it was almost as if the country didn't exist within his mental horizons--America was still something like that upstart colony of the late eighteenth century, a belief that various other English relatives and family friends seemed to share--I remember being practically in tears of rage as a teenager arguing with one particularly superior and condescending asserter of there being nothing "old"--no "history"--in America, in retrospect it is a bizarrely Burkean argument for an English teenager to have been making as late as the 1980s!)