Everyone has an image of a common; to a town dweller it is the much-cherished local open space, often used for exercising the dog, birdwatching or jogging. To the upland farmer it is the moor adjacent to the farm, with grazing rights passed down from previous generations. To a nature conservationist, however, commons are becoming an increasingly important stronghold for wildlife habitats that are rapidly declining throughout England and Wales, but which find protection under the complexities of common land law.