St Albans sinkhole
Workers attempt to fill a sinkhole which appeared in St AlbansReuters/Eddie Keogh

A large sinkhole has suddenly appeared in a road in Hemel Hempstead, Hertfordshire: 17 properties have reportedly been evacuated but there are no reports of any injuries.

Last week a smaller sinkhole appeared in the M2 motorway near Sittingbourne in Kent and a 30-foot crater appeared in a drive in St Albans earlier this month, swallowing a car which could not be recovered.

Also last week a sinkhole which opened up beneath a Corvette museum in Kentucky swallowed up eight rare cars. In February 2013 a man was killed when a sinkhole swallowed up his bedroom in Seffner, Florida.

Guatemala City sinkhole
A giant sinkhole caused by the rains of Tropical Storm Agatha is seen in Guatemala CityReuters/Casa Presidencial/Handout

Sinkholes often appear when rain water seeps down through soil to soluble rock such as chalk or sandstone. Over long periods of time – sometimes thousands of years – the water, particularly if acidic, slowly erodes the rock and eventually there is a collapse.