Where the city ends, and the countryside begins, is something we think about a lot round here. We’ve discussed whether the boundaries of London should be extended; we’ve explained why the official placing of city limits can make it a right pain to compare two different cities.

This is the sort of thing urban geeks can happily debate among themselves for hours (honestly, you should come to one of our parties, they’re brilliant). But normally, one might think, the exact placing of administrative lines on a map would be of largely theoretical impact.

It isn’t. It can have a real, and horrible, impact.

Consider Oxford. The home of England’s oldest university has a housing crisis – on some measures, in fact, the worst housing crisis in Britain – and so could do with a few thousand extra houses. Where they should go is a matter of some debate, but in an ideal world you’d probably want them to be as close as possible to the centre, to cut down on traffic and so forth.

Now, consider this map of the city and its environs, put together by the Centre for Cities:

On this map, you can see that there are not one, but two, things holding back Oxford’s growth. The obvious one is the lack of land available for building, thanks to the stranglehold imposed by the greenbelt. This is a huge problem, but it’s one we already know about, so let’s just take it as read.


The other problem is more subtle. Look at the map again. In many places – in the north, in the east, in the south – the city’s built up area ends almost exactly at the city’s administrative limits. Expanding the diameter of the city by even a couple of extra streets would almost certainly mean extending into neighbouring authorities such as South Oxfordshire or Cherwell.

It would be wrong to say that these areas are entirely insulated from Oxford’s housing problems – some of their residents will be commuters, all too aware of that housing crisis. But they’re certainly not as exposed, since many more of them live a long way away, in places like Banbury and Thame.

To make matters worse, the fiscal incentives for councils in Britain these days are so skewed that local government tends to feel all the costs of population growth (traffic, social welfare, service provision), while the benefits, in the form of higher tax revenues, flow straight up to the Treasury.

The result of all this is that, if you built a housing estate just outside the city limits in Cherwell, it’d be quite good for the residents of Oxford, who’d probably see their housing costs come down. But Cherwell council will be all too aware that it imposes massive costs for relatively limited benefits, and they are going to fight tooth and nail to make sure it doesn’t happen. And that council, remember, still has substantial control over the planning system.

What all this means is that it would be surprisingly difficult to solve Oxford’s housing crisis even if the greenbelt wasn’t there.

Fixing this would mean ensuring that the people who bear the costs of growth have more to gain from it, too. That probably means fiscal devolution. But it also means rethinking the boundaries of our cities, so that they look a lot more like functional economic units, such as the government’s officially defined “travel to work areas”:

That isn’t going to happen any time soon – no one has much appetite for ripping up the administrative map and starting again. But if our cities are ever to work properly, it probably should.