Lars Tharp 's five-part series looking at clay as a universal substance in the story of man. 3: On the Tiles. Member of the Tile Society and avid tile collector Chris Blanchett , who has some 6,000 tiles in his house, tells the story of their decorative, architectural and practical purpose, while Sebastian Wormell , the archivist for Harrods, explains their use on the outside of the building and their importance to the food and meat halls within. Producer Anne Bristow