Londoners looking at pictures of masked Beijing residents groping their way through thick smog will feel both sympathy and a sense of deja vu - 63 years ago, more than 6,000 people died when a combination of factors triggered what locals called a peasouper.

London's smog was a disastrous mixture of an unseasonal anticyclone, cold weather, postwar austerity, unchecked factory emissions, and Victorian-era houses.

In the aftermath of World War II, Britain was tired and broke. All the finest Welsh coal had to be exported to raise money to pay bills incurred during the war, yet most homes were heated by open fires; double-glazing with central heating was something only our rich American cousins had. All Londoners could afford was poor-quality "brown coal", which sputtered in the grate and smoked furiously.