Urine as a garden fertiliser, sewage as gas for heating, weeds that keep the pests away from your vegetables - they're all examples of ways in which natural resources can make our lives cheaper and easier. So why aren't they used in everyday life?
John Howard visits the National Centre for
Alternative Technology at
Macynlleth in mid-Wales in a special live edition.
Producers JOHN WATKINS and RICHARD WACHMAN