Kim Gittleson travels to the heart of Sardinia to find out about a revolutionary new trading system called Sardex. The concept of 'mutual credit' was hatched by the Babylonians more than 4,000 years ago. Today more than 8m euros worth of goods and services are exchanged every month in Sardinia through its modern equivalent. We hear from Giuseppe Littera about the inspiration for Sardex, and business owners on the island tell us about its benefits for the local economy. London School of Economics professor Paolo Dini explains the concept of local currencies, and Marco Lotta from the Agricola Campidanese tells us why the island’s rural economy needs to develop if it is to provide food and jobs for its people. (Photo: A beach near Porto San Paolo on the eastern coast of the Italian island of Sardinia, Credit: Getty Images)