December 9, 1952: London fog clears after days of chaos

The Great Smog of London

Sunshine has returned to the capital following four days of dense fog in which London transport was brought to a standstill. The atrocious conditions led to widespread disruption of rail, road and air services and affected shipping on the River Thames.

As freshening winds and milder temperatures dissipated the fog today London buses and coaches ran normally but still with some delays on the Southern Region railway.

The fog, which began on 5 December, also affected other areas of the south-east, with icy roads causing several road accidents. Ambulancemen and firemen had to walk ahead of their vehicles to reach those in need.

It also spread as far as northern France, Belgium and the Netherlands.

A cross-channel ferry carrying 300 passengers from Folkestone to Calais was 15 hours late. The ship had to anchor off the French coast, unable to get into port due to poor visibility.

The Great Smog of London, or Great Smog of 1952 sometimes called the Big Smoke, was a severe air-pollution event that affected the British capital of London in early-December 1952. 

A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants – mostly arising from the use of coal – to form a thick layer of smog over the city. It lasted from Friday, 5 December to Tuesday, 9 December 1952 and then dispersed quickly when the weather changed.

It caused major disruption by reducing visibility and even penetrating indoor areas, far more severe than previous smog events experienced in the past, called "pea-soupers". Government medical reports in the following weeks, however, estimated that up until 8 December, 4,000 people had died as a direct result of the smog and 100,000 more were made ill by the smog's effects on the human respiratory tract. More recent research suggests that the total number of fatalities was considerably greater, about 12,000.

London had suffered since the 1200s from poor air quality, which worsened in the 1600s, but the Great Smog is known to be the worst air-pollution event in the history of the United Kingdom, and the most significant in terms of its effect on environmental research, government regulation, and public awareness of the relationship between air quality and health. It led to several changes in practices and regulations, including the Clean Air Act 1956.