We meet the writer and cultural historian Kassia St Clair on Cable Street in East London, site of the invention of the first synthetic purple dye, and an appropriate setting for discussion of her books The Secret Lives of Colour and The Golden Thread. Kassia’s first book told the story of 75 unusual colours, from amber to absinthe, while its successor spoke of everything from the woollen sails of Vikings to Michael Phelps’ swimsuit. Between discussing the unusual paths of certain colours, we find out how Kassia’s own passion for colour began in her mother’s flower shop.