In 2012 Prince Charles earned more than £18 million from the Duchy of Cornwall, but how much do we know about this secretive estate? A Channel 4 Dispatches investigation reveals the scale of its hugely profitable property empire and looks at the amount of tax Prince Charles is paying. As the heir to the throne, Prince Charles inherited the Duchy of Cornwall: a vast array of farming, residential and commercial land and properties, as well as a multi-million-pound financial investment portfolio. Each year the duchy helps fund Prince Charles' princely lifestyle. While the duchy's public image is one of rolling countryside estates, organic farms and classical architecture and environment, some of its investments tell a rather different story. Reporter Antony Barnett takes a royal tour of some surprising properties that the duchy might prefer you not to know about. With the tax arrangements of wealthy individuals and major corporations making headline news, these Dispatches findings come as Parliament's Public Accounts Committee prepares to launch its own inquiry into why, unlike other commercial businesses, the duchy does not pay corporation tax or capital gains tax.