The greenbelt is a sacred cow, right? Everybody loves the greenbelt, everybody wants to see it protected, and everybody knows it. A politician advocating a relaxation of greenbelt constraints might as well advocate abolishing the NHS, exiling the royal family and banning football.Extrapolating from my own limited experience, the above is a fair summary of how people who work in the area of housing and planning (broadly defined) see the debate going. A fair few times, I have heard comments like “Between you and me – I completely agree with you. But I could obviously not say that in public. It’s a lost cause; it’s just never going to happen.”The problem with this kind of defeatism is that it becomes self-fulfilling. Look, I am not one of those who believe that opinion formers can shift the Overton Window (the spectrum of ideas that people will at least give a hearing, as opposed to dismissing them as ‘obviously bonkers’) at will. I believe that there are quite a few subjects on which most people have made up their minds, and will not change them, no matter what anyone says or writes. But I also believe that the greenbelt is not one of those subjects, and that this defeatism is, well, self-defeating.Let’s have a look at some of the survey evidence, which, at first sight, seems to confirm the defeatists’ position. According to a recent poll commissioned by the Campaign to Protect Rural England (CPRE), an anti-housebuilding pressure group, two thirds of the public are opposed to greenbelt development.However, in the same poll, one in three people also say that they know nothing about the greenbelt, including one in four people who have never even heard of it. Bear in mind that this is self-assessed knowledge, and in surveys of this kind, people tend to overestimate or overreport their knowledge of a subject. Awareness of greenbelt policy is particularly low among groups that you would expect to be disproportionately in favour of housebuilding: private tenants, the young, those in social grades D and E, and Londoners. Call me naïve, but if somebody claims to support a policy that, at the start of the interview, they didn’t even know existed, I would suspect that their views on the matter are not yet that firmly settled.Would people be less supportive of greenbelt policy if they knew more about it? The Barker review contains a survey which offers some interesting insights on this. It simply asked people what types of land they think should remain undeveloped, irrespective of official land use designations and classifications. Unsurprisingly, most people want to see land which hosts wildlife and land “with significant landscape or scenic beauty” protected, and the protection of green spaces within urban areas also enjoys high levels of support. Fair enough – these are the boxes I would have ticked myself, had I taken part in the survey. But interestingly, only just over 15% believe that land should be protected solely by virtue of being located on the edge of a town or city. That, of course, is precisely what the greenbelt does.The short summary is that the vast majority of people are not supportive of the greenbelt unless you call it ‘the greenbelt’. People like the name, not the policy. Why is that? Because, as a survey by Natural England shows, people take the term ‘greenbelt’ at face value: they believe that the greenbelt is literally green. The survey asked people about their associations with the term, and it turned out that woodland, nature reserves, country parks and community forests top the list. Almost nobody thought of derelict land, quarries etc, although the greenbelt does, of course, have its fair share of unattractive land. In the US, greenbelts are called ‘urban growth boundaries’, and that is one Americanism which I would love to see entering British English, because it would spell the end of the policy. ‘Save our greenbelt!’ makes a good battlecry, ‘save our urban growth boundary!’ not so much.Regular readers of this blog will be aware that I don’t hold anti-development campaigners in particularly high regard. But in this case, I think the blame lies not primarily with the Nimbys, but with the defeatists – those who know better, but who refuse to say so in public, having convinced themselves that the whole thing is “a lost cause anyway”. Well, if nobody ever explains that the greenbelt is not exactly the Shires from The Lord of the Rings, then of course the public will see calls for a relaxation of greenbelt protection as an extreme fringe opinion.I once saw an American poster which read “If half of the people who say that a vote for Ron Paul is a lost vote actually voted for Ron Paul, it would not be a lost vote’, or something to that effect. Ditto for greenbelt reform. It is currently politically unfeasible because the people who should make the case for reform keep saying that it is politically unfeasible. The way to make it politically feasible is to stop saying that it is “not going to happen”, and to start explaining why it should happen.Dr Kristian Niemietz is the IEA’s Head of Health and Welfare.