When economic historian Charles Kindleberger charted the rise of financial centers around the world in 1973, he doubted London could take the top spot in Europe’s growing union of states: "Sterling is too weak, and British savings too little.” Instead, after assessing various cities’ economies of scale and corporate pulling power, he plumped for Brussels.

He was clearly betting on the wrong horse, but Kindleberger’s treatise should still be top of European regulators’ reading list on the eve of a potentially messy end to decades of unfettered free trade with Britain.

His insights into the forces that make or break a financial center resonate in post-Brexit Europe. Over-centralization carries big risks, bringing what he called "diseconomies of scale,” such as information bottlenecks, spiraling overheads and interference by politicians. His work is a challenge to those who scoff at the idea that London could ever face any serious competition.