Graeme Wall wrote:

Cities have a natural footprint limit. The generally accepted limit
is that if it takes over an hour to travel from one side to the
other its expansion naturally tails off.

Explain supercities then.

London, New York, Tokyo might give you a clue. Keep looking.

Try getting across any of those in an hour.


London developed largely by expansion of its sattellite towns and villages
in the commuter belt to the point that they fused into one another before
the limits of the greenbelt were set, and then later local government
reorganisation came along and fused them together. It's somewhat different
from a town expanding outwards until it hit its limit.

One could have a more than semantic discussion about what "London" is - very
few people use "Manchester" to mean the whole Greater Manchester area, and
try applying "Birmingham" to the West Midlands county, but with London it's
somewhat more confused with the two terms frequently used interchangeably
(look for instance at the current government arrangements with the "Greater
London Authority" consisting of the "Mayor of London" and the "London
Assembly"). The argument about whether the outer London zones are "London"
usually boils down to the Royal Mail policies, but the strong local identity
in at least some of the suburbs and the history of absorption rather than
straight on expansion makes it a more open question.

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