The scale of the threat to the green belt is revealed today with a report highlighting more than 35 proposed developments on protected land. Local authorities are under growing pressure to rip up countryside-planning rules by approving dozens of building projects including mines, industrial parks and 81,000 homes, according to the Campaign to Protect Rural England (CPRE). Government policies requiring councils to allocate more than five years' worth of land for new housing is opening up large swaths of England's 1.6 million-hectare green belt to developers, the CPRE warns. Ministers risk "destroying the countryside" with a construction boom aimed at kick-starting the economy, campaigners say. About 12 per cent of England is designated as green belt, designed to stop urban sprawl, protect the setting of historic towns, safeguard the countryside from encroachment and promote urban regeneration and the reuse of brownfield land.