One of the things that London is most famous for is the thick black fogs that often occurred in the city’s past. Shakespeare vividly described one as a “drooping fogge as blacke as Acheron” and right up until the 1960s they were a common feature of London life.

Often so thick that they were colloquially known as “peasoupers”, London fogs could last for amazing lengths of time, often for several weeks at a time. In the winter of 1879-80 one lasted from November until March!

Not only long, the fogs could sometimes be deadly - one as recently as 1952 caused an estimated 4,000 deaths.

The main cause of the fogs was the burning of coal within the city. The vast number of houses and industries that burnt coal meant that the emissions caused massive pollution, and if there was no wind to blow the smoke away the result was thick black fog.

At last in 1956 a Clean Air Act was passed which banned the burning of coal within London, a ban which is still in effect to this day. The desired effect has been achieved for London’s last major fog occurred in the winter of 1962.