Look carefully, and you will see this map was produced by someone called Sevrin Waights. This is his web site at the LSE.
But what interests me about this is the difference between London, and to a lesser extent Oxford and Cambridge, those two red pillars either side of the tower that is London, and the absence of any premium within other green belts, e.g for Birmingham. Manchester, Leeds or Bristol. Unless there is a bit of a spike there for Manchester.
It got me thinking as to what you'd expect. Here in London - although maybe it's a result of playing Monopoly - we're so used to the idea of high land values in city centres, that we don't see it as abnormal, and however high land values are, we just see the pattern, without quantification, and see it as normal. But this infographic shows this ain't necessarily so. As a Londoner, it's tempting to ask who'd want to live in Birmingham anyway, although it's really not such a bad place. And Manchester definitely does have something going for it, without (in 2007 at least) silly land prices as in London. So it really doesn't have to be like that, but also, you can't just blame green belts.
I wish I had time to research this more, although thanks to a Twitter conversation, I have some leads to follow. However, some possibly simple minded economics suggests that it's just about supply where people want to build, and that the case of Manchester, within its green belt, where the supply will be of existing developed land, it is easy enough to redevelop such land to stop prices going crazy. In the jargon, there is high elasticity of supply. And if in Manchester, why not also in London, Oxford or Cambridge?
Of course London is a bit different, since it's a global city on a scale which Manchester is not, so is subject to far greater demand, especially from overseas. Short term elasticity of supply is always going to be lower - that's just another way of saying, even with the best will in the world, it takes a bit of time and effort to get round to planning development. So it's reasonable to expect some kind of spike in London land values, but surely not that much, especially since, any sensible investor, should understand that supply will eventually be forthcoming, so undermining the value of land they pay up for. Another way of putting this is to say that even without green belts, you'd expect there to be a price spike in major global cities - but how much? There's another question I don't have answers to, and it's made harder to answer because other global cities do have comparable planning restrictions - thinking here of Paris and New York. Maybe there's a pattern here, which is that in such global cities, groups with political influence develop with a vested interest in restricting the elasticity of supply - a bit like medieval guild masters would restrict outsiders coming in to their towns to practice their crafts.
