From Mr Michael Woolfolk.

Sir, Your latest editorial on the future of the eurozone ("A currency union needs markets", May 3) leads with a provocative question: is it possible to have a monetary union without political union? You begin by addressing a more fundamental question: is it possible to have a common currency in countries without a flexible market economy? Certainly, many eurozone politicians would like to think so and are vigorously arguing against the inequities apparent in flexible market economies. Without a doubt, capitalism does have its dark side.