Greater London Built-up Area

Outside the region's administrative boundary, it includes contiguous suburban settlements and a few densely populated outliers connected to it by ribbon development.

[citation needed] As a selective grouping of relatively low- to mid-density (and some high-density) output areas, each consisting of roughly 120 households,[2] it can be compared to the London region, which covers 1,572 square kilometres (607 sq mi) and contained 8,173,194 residents at the time of the 2011 census.

Then, with continued economic growth and the expanding networks of public transport, people (particularly the middle-class) would then slowly migrate towards the suburbs, gradually softening the population density gradient.

A dramatic increase in the city's urban sprawl began in the nineteenth century when labourers flocked from the countryside to work in the new factories that were then springing up.

Large developments of small terraced houses began to appear and the new public transport systems – (the Tube, buses and trams) – allowed workers to commute into the city daily.

By the mid-nineteenth century, the first major suburban areas were springing up around London as the city (then the largest in the world) became more overcrowded and unsanitary.

[6] Harrow was reached in 1880, and the line eventually extended as far as Verney Junction in Buckinghamshire, more than 50 miles (80 kilometres) from Baker Street and the centre of London.