Real cities have a habit of stymieing the best-laid plans - such as those for London after the Great Fire of 1666, including Richard Newcourt’s famous grid-plan design. London’s loss, if such it was, was America’s gain. Eaton recounts how America was fertile ground for British and French Utopianists, and social reformers such as Robert Owen, creator of New Lanark in Scotland, went there with huge optimism. Many of the ventures failed, including Owen’s experimental 19th century community of New Harmony: an example that succeeded is the earlier Philadelphia (“city of brotherly love”), not least because the physical gridiron planning was accompanied by a pioneering attitude towards religious and social tolerance on the part of Governor William Penn.

And what do we have, in Britain? We have various paternalistic industrial and agricultural villages such as Port Sunlight or Bourneville. We have a few “garden cities” such as Letchworth and Welwyn. We have Bath, Milton Keynes, the Nash terraces and villas of London, the Barbican, and sundry other fragments of Le Corbusier-influenced postwar planning, some successful, others not. It doesn’t add up to a lot, really, but that is because true Utopias must be perfect, thus must always remain unbuilt. Like the newly fashionable psychedelic dreams of the 1960s Archigram group with their Plug-in, Walking and Instant Cities.

Eaton concludes that past Utopian experiments were simply too ambitious, particularly in the 20th century. For the 21st, she says, Utopianists must act local - within a global framework, mind you - and must “acquire a new modesty”. This sound dangerously like pragmatism to me, and since when was Utopia ever pragmatic? But it is true that the world may now be too small for a real, no-holds-barred, all-new urban Utopia, even one planned in the world’s tallest tower, as our own Lord Foster did in the 1990s. Those old ruralists William Morris and Frank Lloyd Wright might just have been right all along.