As Dame Ellen MacArthur circumnavigated the globe she got first-hand knowledge of the finite nature of the world's resources. When she retired from sailing she created a foundation to promote the concept of a 'Circular Economy' - where resources are re-used and waste reduced to zero. Many companies around the world - including some of the biggest, like Unilever - are responding to her ideas.
Peter Day talks to the record-breaking sailor, to Unilever, and to the creators of an innovative urban farm in New Jersey about why these concepts are so important and how businesses can take them on board.