By the end of the nineteenth century London was at the limit of the density industrialisation had produced: coal smoke, overcrowded housing, epidemics. The countryside, meanwhile, lacked work and services. In a book published in 1898 Ebenezer Howard, a court stenographer, framed the problem not as a choice but as the absence of a third option, and drew his famous diagram of the three magnets: town, country, and a town-country combining the attractions of both.

His proposal is concrete. Towns capped at 32,000 people, with industry and housing separated, parks and public buildings at the centre, ringed by a permanent agricultural belt; growth is met not by expanding the town but by founding another. The radical part is ownership: the land is held in common by a trust, rents return to the community, and increases in value accrue to the town rather than a private owner. Howard presented this as a model to be built through cooperation rather than revolution.

Letchworth (1903) and Welwyn (1920) are the two towns where the idea was applied; both were built and both survive, though the ownership model was partly diluted. Its influence exceeded its execution: Britain's post-war New Towns programme, Radburn in the United States, suburban settlements in Germany and Scandinavia, and Turkish examples such as Ankara's Bahçelievler descend from it. The criticism continues too — low density produces dependence on the car, and in most places the model was copied as 'suburb with gardens' without its social programme. The green belt, meanwhile, remains central to the British planning system.