Surprisingly the British Isles are home to seven species of crayfish. Only one, the white clawed crayfish, is indigenous; once a common sight along British rivers, it is now endangered, due partly to the release of its North American cousin into British rivers 30 years ago. Lionel Kelleway travels to Somerset to investigate the plight of our largest freshwater crustacean and to see a project to try and save the crayfish in the wild. Show less