Drivers have been surprised to see salt spreading the night before the warmest February day in 100 years.

Signs notifying motorists of the spreading were put on the M20 while workers have been seen carrying out the work elsewhere last night with temperatures between 8C and 10C.

One driver said it was "odd" that preparations were being made for frost and ice following a week of warm temperatures culminating in the warmest February day in a century - reaching a comfortable 18C in some areas.

A spokesperson for Highways England confirmed staff were spreading salt on the M20 between Junctions 3 and 9 last night.

"We use Met Office weather data and according to that temperatures were expected to drop below zero with a possibility of frost forming," they said. "When there's a risk that temperatures get to a certain point we have to go out otherwise there's a risk to motorists."

The agency has no plans to carry out salt spreading tonight.

A Kent County Council (KCC) Highways spokesperson also said that their workers were preparing roads for a freeze.

"A decision on whether to grit the roads is made by road surface temperature which is different from the air temperature," they explained. "People are often surprised about the differences between the two temperatures."