British density

Britain is often described as crowded. London? Well, it seems stupid even to ask the question: of course it’s crowded. But I’d like to flip the question around. How much space can a person in Britain reasonably expect? And, for comparison, how much space does he or she actually have?

Some back of the envelope arithmetic. The UK has a land area of 243,610 km2. The population is 62.5M or so. That gives 3,900 m2 per person, or 0.39 ha. A decent amount. Of course, most people live in urbanised areas; let’s concede that this is desirable for economic reasons. So, how much space can a person living in a British town or city reasonably expect?

Leeds, my home town, has an area of 562 km2 and its population is around 750,000 (source). That gives 749 m2 per person (0.075 ha). But two thirds of this area is designated as green belt (ibid.). For now, let’s accept this planning designation: it curtails the area per person to 250 m2. That’s land area. Of course, we have the technology to build multi-storey structures on the land, potentially increasing the area per person. So there’s a multiplier: the plot ratio. Let’s assume, conservatively, that Leeds can be developed to a plot ratio of 2. This ratio can be taken to allow for open space such as roads and private gardens, and hence a typical structure might be 3-4 storeys. Sounds like a reasonable development goal? OK, then. A plot ratio of 2 gives us 500 m2 per person.

Now, how much area does a person living in Leeds actually have to swing a cat? This is a hard question to answer with elegance or precision, but here goes. Around half of the dwellings in Leeds are classified as having three bedrooms; this is the most common dwelling type (source). Take this as representative. The median gross internal area, for a three bedroom house in the UK, across all tenure types, is 92 m2 (source). If you take it that a three bedroom house in Leeds is lived in by three people (this might be conservative), then around 30 m2 per person looks plausible. So what happened to the other 470 m2? Is it all given over to employment use? Railway lines? Schools? Hospitals? Parks? Is it just wasted? Reserved for grouse shooting? It’s possible I’ve gotten my sums wrong, but I have to say I find this difference – between the space people could have and the space they actually have – just flat out boggling. Call it naivety if you like.

Coincidentally, when the LSE Cities project looked in detail at the Green Street East district of Newham, London, they found 27.8 m2 of habitable space per person, comparable to my (very rough) estimate of living space in Leeds (source). In the same study, the LSE project also looked at the Town district of Hammersmith and Fulham and found 49 m2 per person. However – and this is the interesting part – when measured in terms of persons per hectare, both districts had very similar densities: 176 pers. / ha in Green Street East versus 153 pers. / ha in Town. So in Town, Hammersmith & Fulham, for a given land area, more area is available to people. It’s also the wealthier district of the two. Conceivably, the provision of this extra space in Town is explained by a higher plot ratio, although not necessarily: the only firm conclusion I can draw is that this part of Hammersmith & Fulham just does better at land utilisation. Less land is wasted: more is converted – perhaps by building higher – to habitation. Which is what we want, right?

Update: On re-reading this, it occurs to me that a problem with the topic might be equivocation over the term ‘density’. Building taller increases built form density but doesn’t have to result in higher population density (and perhaps shouldn’t). A lot of UK discussion focusses on population density while glossing over the issue of habitable space. For example, Ed Glaeser:

We maximise our damage when we insist on living surrounded by greensward. Lower densities inevitably mean more travel, and that requires energy. While larger living spaces certainly do have their advantages, large suburban homes also consume much more energy. Anyone who believes that global warming is a real danger should see dense urban living as part of the solution.

This misses something important. Energy-intensive ‘sprawl’ is bad, yes, but people like living space; we should somehow try to arrange things so that they can have more of it.

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