Philip Marlowe has become the iconic American detective anti-hero, so it's no surprise his creator was educated at an English public school.
Raymond Chandler was classically educated at Dulwich College. (Other alumni included P.G. Wodehouse and C. S. Forester.) In 1907, he was naturalised a British subject in order to take the tough civil service exam, which he passed with the third-highest score. Not long after, he moved to LA, and after barely getting by for ten years, published the novels and screenplays which made him and Philip Marlowe famous. Here's the opening of the Big Sleep.
In 1958, seven months before Chandler died, the BBC recorded Raymond Chandler and Ian Fleming talking about English and American thrillers (scroll down). It's offered as part of a Chandler reappraisal. The two writers are sweet to each other.