BBC Two

18 July 8:00

Inside the Factory

Documentary series. Gregg Wallace receives a load of tea leaves from Kenya and follows their journey through the factory that produces one quarter of all the tea we drink in Britain. Along the way, Gregg discovers that there can be up to 20 different teas in your bag and that the recipe for the blend is altered every day, measured against a standard created in 1978. Meanwhile, Cherry Healey is discovering the secrets of the tea leaf in an African tea processing plant. She learns that 40% of each leaf is made up of chemicals called polyphenols. Historian Ruth Goodman investigates tea adulteration. In the 19th century, there were eight separate factories in London which existed solely to dry and re-colour used tea leaves.