Drivers on Kent's roads have had to take it steady today with much of the county covered in thick fog.

The powerful lights at Gillingham's Priestfield Stadium were definitely required as the home team took on MK Dons this afternoon.

There have been reports of people not slowing down on the M20 and on the Sheppey Crossing where Britain's biggest collision took place in thick fog three years ago.

According to the Met Office, fog is caused by tiny water droplets suspended in the air.

The thickest fogs tend to occur in industrial areas where there are many pollution particles on which water droplets can grow.

It says the official definition of fog is a visibility of less than 1,000m.

This limit is appropriate for aviation purposes but for the general public and motorists an upper limit of 200m is more realistic.

However, it is likely to be gone tomorrow with thick cloud and temperatures of 10C expected.