A nightingale choked in Berkely Square

"Who's there?" I called sharply.

I turned and looked across the room. The window had been widely opened when I entered, and a faint fog haze hung in the apartment, seeming to veil the light of the shaded lamp. I watched the closed door intently, expecting every moment to see the knob turn. But nothing happened.

"Who's there?" I cried again, and, crossing the room, I threw open the door.

The long corridor without, lighted only by one inhospitable lamp at a remote end, showed choked and yellowed with this same fog so characteristic of London in November. But nothing moved to right nor left of me. The New Louvre Hotel was in some respects yet incomplete, and the long passage in which I stood, despite its marble facings, had no air of comfort or good cheer; palatial it was, but inhospitable.

I returned to the room, reclosing the door behind me, then for some five minutes or more I stood listening for a repetition of that mysterious sound, as of something that both dragged and tapped, which already had arrested my attention. My vigilance went unrewarded. I had closed the window to exclude the yellow mist, but subconsciously I was aware of its encircling presence, walling me in, and now I found myself in such a silence as I had known in deserts but could scarce have deemed possible in fog-bound London, in the heart of the world's metropolis, with the traffic of the Strand below me upon one side and the restless life of the river upon the other.

The mysterious, swirling London fog was an essential staple of pulp fiction without which much of the aura of foreboding would have been impossible. In an era when people are accustomed to imagining a cleaner environmental past, it's a shock to realize those fogs really did exist -- and not simply in fiction.

For hundreds of years, the mists and fogs of Britain's major cities were all too often polluted and noxious, with London especially badly affected. ... The smoke-laden fog that shrouded the capital from Friday 5 December to Tuesday 9 December 1952 brought premature death to thousands and inconvenience to millions. An estimated 4,000 people died because of it, and cattle at Smithfield, were, the press reported, asphyxiated. Road, rail and air transport were almost brought to a standstill and a performance at the Sadler's Wells Theatre had to be suspended when fog in the auditorium made conditions intolerable for the audience and performers.

The estimate of 4,000 human deaths is derived from the spike in mortality that occured in that period as the pollution-laden fog smothered the old and infirm. Note how the graph of deaths takes off from the fifth of December.

National Public Radio carries a contemporaneous account of what it was like to be in London that December in 1952.

Roads were littered with abandoned cars. Midday concerts were cancelled due to total darkness. Archivists at the British Museum found smog lurking in the book stacks. Cattle in the city's Smithfield market were killed and thrown away before they could be slaughtered and sold -- their lungs were black. On the second day of the smog, Saturday, Dec. 6, 500 people died in London. When the ambulances stopped running, thousands of gasping Londoners walked through the smog to the city's hospitals. The lips of the dying were blue. Heavy smoking and chronic exposure to pollution had already weakened the lungs of those who fell ill during the smog. Particulates and acids in the killer brew finished the job by triggering massive inflammations. In essence, the dead had suffocated.