'Asunny place for shady people," was W. Somerset Maugham's pithy summation of Monaco, the tax haven and wealthy resort in the south of France close to where the writer lived for much of his life.

Whether or not Maugh-am's works occupy a place on the bookshelves of financial regulators, the authorities have spent the past decade turning the screw on the growing number of tax havens that have sprung up around the world.