It’s chastening to realise that, since Soft City’s first publication in 1974, the book’s citizens, nearly all in their go-getting 20s and 30s, have moved on to the world of bus passes, if not the Great Beyond. It’s sic transit gloria mundi time for the pioneer knockers-through who gentrified Islington, the vegan squatters of Notting Hill with their I-Chings and ouija boards, the band of young writers in the Pillars of Hercules pub on Greek Street, the rival salons of Holland Park. The girls who affected granny glasses are grannies themselves now. I live in Seattle, where I moved in 1990, and so my increasingly imaginary London still has Muriel Belcher presiding over the Colony Room, otherwise plain “Muriel’s”, and Gaston over the French Pub, you can lunch at Mario and Franco’s Trattoria Terrazza (“The Trat”), two can dine at L’Escargot, with a carafe of house red, for around £7 (or five review-copies sold to the literary knackers’ yard, owned by another Gaston, off Chancery Lane), and you can still smoke on the Tube.

Yet in Soft City I was trying to write about metropolitan life as it had existed since the 18th century – as a theatre in which the newly arrived could try on masks and identities more daring and extravagant than any they had been allowed in their villages or small towns, as a place that guaranteed a blessed privacy, anonymity and freedom to its inhabitants and, most of all, as somewhere where every citizen created a route of his or her own through its potentially infinite labyrinth of streets, arranging the city around them to their own unique pattern. That was why it was soft, amenable to the play of each of its residents’ imagination and personal usage. A town, even a large one, imposes on its people certain fixed patterns of movement and, with them, a set of rather narrow expectations of what kind of character you’re permitted there. If I live in Worksop, Worksop largely defines me; if I live in a great city like London or New York, I can make the city up as I go along, shaping it to my own habits and fancies. In an article published a few weeks ago in London’s Evening Standard, David Sexton cited Soft City and nicely summed up its essential argument in one sentence, writing that the book was about “how we all construct our own different versions of London, in our imaginations joining up the streets and places each of us knows, so that associations and familiarities matter more than the map and thus we all mould for ourselves a different city in which to live”. Aboard his newly bought bicycle, Sexton was busily discovering the intricate geography of his own soft city.