The concept of the green belt was first introduced back in 1935 as a special land designation wrapping around the major cities (and some larger towns) in the UK in order to protect the sense of openness in the natural context. Without strict guidance, it was predicted that high levels of urban sprawl would dominate the natural context; with new developments consuming all available land as the population rapidly grows. The green belt acts as a protective barrier to this - reducing people's ability to build on the surrounding rural areas, thereby ensuring the continued protection of biodiversity and forest lands.
