London:'Walked in the streets for two hours, weightless, boneless, bodiless." So wrote Franz Kafka of a nocturnal drift through Prague, feeling himself scarcely human: a wraith among shadows, a thing of the night, immaterial. The idea that the city after dark is a place, literally, to lose yourself remains appealing, even as the boundaries blur between the workaday diurnal world and its negative twin.
Even in the 19th century, with the spread of gas lighting, it seemed that night was on the wane, snuffed out by overlit offices, garish entertainment and state surveillance. But as Sukhdev Sandhu's svelte and suggestive book discerns, there is still some imaginative mileage in a trek through the city at night: his London preserves secrets unseen by commercial interests, wide-awake clubbers or infrared CCTV cameras.
Night Haunts started life as a series of essays commissioned by Artangel, the organisation responsible for staging such ambitious art projects as Rachel Whiteread's House and Jeremy Deller's filmed re-enactment of The Battle of Orgreave. Sandhu's contribution to Artangel's two-year Nights of London programme was a journey into a realm unknown to most Londoners, let alone tourists drawn to its nightlife as well as its daytime attractions. The result is a book that may lack the historical heft of Peter Ackroyd's biography of the city, or the visionary insight of Iain Sinclair's prose hikes among its ruins; but Night Haunts is in a way all the more instructive for its zoom-lens view of London. In his first book, London Calling, Sandhu tracked the way the 20th-century city looked to black and Asian writers; here, he discovers ordinary Londoners, many of them again immigrants, who seem to inhabit the London of Stevenson, Conan Doyle or Dorian Gray.
'Each of the book's 12 short chapters is devoted to an individual or group for whom the night is a kind of home. To the average Londoner, these people exist at the edge of visibility, but they see everything. There are the members of the Metropolitan Police Air Support Unit, whose helicopters give them a view of the city that Sandhu calls "the panoptic sublime": they can spy the logo on a shirt at 2,000 feet, or peer into office windows eight miles away. There are African cleaners who, arriving for work, view the nightlife around them as a "collective insanity". And there are Asian mini-cab drivers who think of their windscreens as film cameras, their rear-view mirrors as microscopes through which they examine unattractive specimens who remain immune to their very existence.
MUCH THAT SANDHU unearths seems to survive from another, obsolete or forgotten, town. Where Paris, for example, has turned its sewer system into a noisome tourist trap, London's cramped conduits will never achieve heritage status. Such is the quantity of fat sluiced into the sewers, where it hardens into a foul scurf, that teams of 'flushers' are employed to shovel it away or, as in the case of an "iceberg" of solid grease below Leicester Square, hack at it hopelessly with pickaxes long into the night. On the turbid Thames, eight barges (there were hundreds even half a century ago) still toil upriver at night from almost derelict docks at Northfleet, and their crews sometimes spot swollen corpses in the light from riverside restaurants. It is all straight out of Our Mutual Friend: even the graffiti artists seem like Dickensian ghosts, shivering and watchful.
There is, says Sandhu, a spirited, phantomic London at work just the other side of dusk. It is at times literally spectral: he shadows Norman Palmer, an exorcist unofficially employed by churches and local authorities, as he circles the site of an old gaol in Clerkenwell: local residents are convinced that the shades of Victorian thieves, murderers and Fenians have been disturbing their sleep. Other voices, more haggard even than the ghosts', haunt the London night: the voices of the desperate ones who phone the Samaritans in the small hours: "there is nothing to be done at 3am except hold on". Meanwhile, in a convent at Tyburn, a community of nuns is taking it in turns to keep a vigil into the night, praying for the souls of the Londoners asleep around them.
Except that more and more of them are not sleeping at all. Londoners, with their long working hours, bad diets and constant stimulation, are among the worst sleepers in the world. Instead, they wander the streets, wide-eyed, aching and fuddled in the head, occasionally catching the eye of a fellow-sufferer and turning away in shame. Even the sleep technicians who try to help, and whose hospital ward Sandhu visits, have become raging insomniacs. In the end, Sandhu himself succumbs: by the time he finished Night Haunts, a book of lucid dreams about a city that only ever dozes, his sleep pattern was in shreds.
Brian Dillon is author of In the Dark Room (Penguin, 2005) and an editor of Cabinet, a quarterly of art and culture. He is working on Tormented Hope: Nine Hypochondriac Lives, to be published next year
Night Haunts By Sukhdev Sandhu Artangel and Verso, 144pp. £10.99