Lucy Worsley, chief curator of the historic royal palaces, focuses on the bathroom - a room that didn't even exist in many British homes until 50 years ago. From the medieval bath houses to London Bridge's communal loos to finding out how piped water got to our homes and finally getting to the bottom of the Crapper myth at Stoke's Toilet Museum, Lucy tracks how our attitude to washing has changed over the centuries and the development of what we think of now as the most essential room in the house.