In the same way that it is US generals directing operations in Iraq, so the Americans are setting the pace in London. It is a shift that has gone largely unnoticed, little commented on and seamless as US banks flex their considerable muscle here. But it has profound repercussions for the Square Mile, which must come to terms with the fact it faces becoming an overseas branch of headquarters in New York. In nearly all respects, in the City, as in the Gulf, America is calling the shots.