One of George Orwell's most vivid characters is George Bowling: a fortysomething insurance salesman with two kids and a growing paunch, in the novel Coming Up for Air. He articulates the near-panic of 1930s England in the grip of the most dramatic housebuilding boom before or since. Bowling complains: "Do you know the road I live in - Ellesmere Road? Even if you don't, you know 50 others exactly like it. You know how these streets fester all over the inner-outer suburbs. Always the same. Long, long rows of little semi-detached houses, as much alike as council houses and generally uglier."
As Natural England, the government's statutory body to protect wildlife, nervously launches a debate into the role of the green belt, it's worth remembering the origins of the policy in this feverish anxiety that England was being carpeted in mock-Tudor semi-detached homes. Four of the five founding principles of the green belt in 1955 were about choking off this suburban spread. Forget the idea that this kind of suburb is actually pretty popular - low density, plenty of green space and gardens - and that it represented a huge improvement in living standards for many. This emergence of a houseproud mass consumer culture prompted a deeply snobbish horror. The choice of words is revealing: this belt would hold urban England in.
The marvel is that through its 50-year history, the green belt has become a sacred symbol for middle class conservationists. If you want a row with the Daily Mail, the green belt is near the top of the list. Part of this is based on a widespread myth: according to an Ipsos/Mori poll, 60% in 2006 thought that green belts were to protect wildlife, 46% to preserve areas of natural beauty. But they are no such thing; green belts include abandoned industrial sites, nondescript agricultural land - in fact there is often nothing green about them at all. That was never part of their founding remit, and sadly it has not become so since.
It's not that green belts haven't done a useful job. The last cited purpose in the original policy paper has perhaps proved the most successful; green belts have helped focus urban regeneration and prevented the doughnut scenarios of American cities, where pleasant suburbs ring a central no-go zone. They've helped ensure the character of historic towns, they've ensured green spaces even in densely urban regions - so outer London didn't creep to Beachy Head.
But we need to rethink green belts for two reasons. First, the government has set a target of 3 million homes by 2020 and not all of them can be squeezed into brownfield sites in cities. Homes have to be built somewhere and it makes no sense to protect a bit of scrubland and sacrifice a beautiful landscape elsewhere. Second, the biggest challenge facing Natural England is how we are to adapt to climate change; all the thinking about wildlife is how to ensure there are green corridors or a green mosaic to increase the resilience of the many species under threat - these can't always be shoehorned into existing green belts.
It's not hard to imagine a way to modernise the green belt - transform it into what people have always thought it was: nature reserves with great swaths of forest. Replace the belt concept with spokes on a wheel, bringing green space into the heart of cities. Giving up some undistinguished green belt to much-needed development to fund such schemes is a small price. But there's a danger: these are shark-infested waters with property speculators, ministers and others happy to sacrifice any consideration for the environment for short-term gains, financial or political, while our weak planning system offers little bulwark. It will take terrier-like tenacity to reform England's green belts, but that's no argument for sitting on our hands in a state of paralysed panic.