The green belts that hem in developed areas in Great Britain are set arbitrarily, according to this op-ed in The Guardian, and the boundaries have outlived their usefulness.

John Elledge argues that it's time to rethink the urban growth boundaries, or greenbelts, of U.K. land use and growth policy. Elledge begins the argument by noting the lost opportunities that the policy has embedded into the country.
The creation of the metropolitan green belt fixed the boundaries of London as wherever the suburbs happened to stop. So Goodwood Avenue stops midway at an unconvincing simulacrum of countryside that’s hemmed in by homes on three sides. There are two tube stations within a mile, yet despite the housing shortage, there’s no building on this land. Not because it’s unsuitable; simply because nobody’s ever built there.
Despite the compelling case made for greenbelts at one point in development and land use planning history (a case made capably and sympathetically in this op-ed), Elledge argues that it's time to rethink growth strategy around the country, because a lack of space is a leading cause of the nation's housing crisis.
Elledge acknowledges that neither the nation's prominent politicians, nor residents of the suburbs, support proposals to loosen their green belts. But in the meantime, "[t]hey are selling younger people down the river." But "gradually, the group that benefits from the green belt is shrinking, and the group it blights is growing. Younger people vote now, too."
FULL STORY: Loosen Britain’s green belt. It is stunting our young people

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HUD's Office of Policy Development and Research
HUD's Office of Policy Development and Research
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