Red showers of rain fell over much of England 40 years ago, a spectacle of almost biblical drama. It was even more surreal to have a blistering heatwave beforehand that had left the country sweltering. But the heat suddenly broke and down came huge downpours of rain, which came in an assortment of red, yellow and pink colours.

The next day, July 2, people woke up to an amazing sight — everything outside was covered in an amazing coat of red, orange or yellow sandy powder. Washing left outside was stained, windows were streaked, plants were coated, and so many cars were covered in dirt that water suppliers reported a big surge in demand as people washed everything clean. Frantic callers to the police and councils worried about possible safety risks from what looked like a distinctly unhealthy substance of some sort.

The crisis was actually a heavy shower of Saharan sand. Storms had swept up huge clouds of desert dust from the Sahara, which was swept over Spain on very hot air until it reached the UK and washed down in showers of extremely large raindrops. In fact, the UK gets showered with Saharan sand a few times a year but the evidence left behind is often mistaken for ordinary, humdrum dirt.