`Fog everywhere. Fog up the river, where it flows among green aits and meadows; fog down the river, where it rolls defiled among the tiers of shipping. Fog on the Essex marshes, fog on the Kentish heights.
"Chance people on the bridges peeping over the parapets into a nether sky of fog, with fog all round them, as if they were up in a balloon, and hanging in the misty clouds."
It may well be that that the London fog which swirls through the opening chapter of Bleak House is just a literary device to epitomise the pervasive obfuscation that shrouds the interminable case of Jarndyce v Jarndyce.
And Arthur Conan Doyle, too, may have been merely trying to set the scene when he began Sherlock Holmes's Adventure of the Bruce-Partington Plans with a similar event:
"In the third week of November, in the year 1895, a dense yellow fog settled down upon London. From the Monday to the Thursday I doubt whether it was ever possible from our windows in Baker Street to see the loom of the opposite houses.
"Pushing back our chairs from breakfast we saw the greasy, heavy brown swirl still drifting past us and condensing in oily drops upon the windowpanes."
But in neither case was it exaggeration.
The progress of the industrial revolution in the early 1800s had changed the character of London fogs; as levels of pollution increased, sulphur dioxide combined with oxygen and moisture in the air to form sulphuric acid, and the fogs were identified as a potent hazard to the health of Londoners.
Decade by decade they grew worse and worse, until finally December 1952 provided the ultimate in what "pea-soupers" had to offer.
The fog formed on December 5th, and brought four days of madding claustrophobia. It pressed on windows like an evil enemy; it seeped into buildings and made it difficult to see indoors; and as the days went by the all-engulfing cloud grew yellower and yellower, and brought the city's traffic almost to a standstill.
With the London smog of 1952, those who had campaigned for years against pollution in the city had their case dramatically and most disturbingly reinforced.
In the succeeding weeks the death rate more than doubled and it was reckoned, allowing for "normal" mortality, that the foggy spell had claimed the lives of perhaps 4,000 people in the metropolis alone.
Three years later, and 45 years ago yesterday - on October 2nd, 1955 - London became a smokeless zone.
The Clean Air Act followed in 1956, and its demonstrable effectiveness has proved that certain aspects of the problems of pollution are not totally intractable.