Illustration by Gary Waters / Ikon Images If you drive around southern England, you quickly notice what a lot of it there is – endless undulating fields; huge post-industrial stretches of sheds and crumbling walls; the 1930s sprawl along what were then called arterial roads. Britain is still a country of half-forgotten back roads and nettle-choked corners. But could we accommodate another 10 million busy, bustling British people? A lot of new Britons came here last year. Net migration was around half a million. There was no real public discussion about that, although politicians did say that the Chinese state’s...