It is a commonly held belief among Londoners that their city is a dwarf on the world stage and, lacking the high-rise buildings of Manhattan and Hong Kong, must be very low density. Neither of these beliefs are actually the case.

We have already shown London’s population is larger than the World City average even though its area is smaller. At the metropolitan level, London’s population density, expressed as the number of people per hectare, is well above the median for the World City Ranking and only behind the Asian cities of Singapore, Hong Kong, Shanghai, Tokyo and Seoul.

London’s metro has a higher population density than all the European, American and Australian cities in the ranking. Why then does the myth of London’s low density city still persist?

Part of the answer lies with the size of areas studied when looking at density, and partly with the mistaken belief that cities with skyscrapers accommodate more people per unit of land than traditional mid-rise street patterns.

The urban cores of most cities are considerably higher-density than outlying areas. Because the administrative areas of different cities vary in size and definition, some cover only this urban core, while others cover the same area as the metro region. If the density of Greater London is compared with the very small urban area of Department de Paris, London looks very low by comparison, but the size of the different areas are not comparable. At the administrative area level, Greater London still has a higher density than 12 of the other cities.

Our idea of what densities are possible in cities is often given by small-scale studies of very central areas or neighbourhoods, not the whole city. To illustrate this we have selected central neighbourhoods of varying sizes for which data is readily available in each of the 20 cities. London’s central borough of Kensington and Chelsea has a population density virtually identical to the median of the 20 cities and higher than nine of them. But each of these areas differ widely in size from others.

^{Source: Savills World Research}

The analysis does show that very high densities can be sustainable at neighbourhood level and central boroughs or districts are likely to be higher density than outer ones. Manhattan in New York City, for example, houses 188 people on every piece of land the size of a baseball field (equivalent to one hectare) but this is not sustained over the entire city, where densities drop to 70 people per hectare, let alone over the entire metro area where they drop to just seven.

High density does not automatically mean high-rise. Very small, core areas like San Francisco’s Chinatown accommodate 287 people per baseball field and the Centro district of Madrid, 286. Both of these districts are notable for not housing skyscrapers. Both are a mix of mid-rise, 7-8 storey buildings and lower 2-4 storey terraced city houses, perhaps with a scattering of small towers. Public open space takes the form of streets, some very pleasant and tree-lined. Both environments achieve a higher population density than high-rise, urban Hong Kong – albeit over a much smaller area.

London’s central character is very similar but over a wider range of boroughs and interspersed with a great deal of open space in the form of gardens, squares and parks. Areas of London that are being redeveloped, more in the style of Manhattan, or the centre of Asian cities are unlikely to achieve such high densities when interspersed with London-style proportions of open space.