Drivers in weather-affected areas are being warned by police to only travel if "absolutely essential" after further heavy snowfall and as ice takes hold in freezing conditions.
Severe weather warning for widespread icy roads were issued by the Met Office on Friday morning for south-west England and the Highlands and Eilean Sar, with a severe frost expected across the whole of the UK.
Gavin Robbins, a forecaster for the Met Office, said most of the UK would get off to a bright start with snow showers only affecting Northern Ireland and the North West. Overnight temperatures dipped to as low as -20.1C in Braemar, Aberdeenshire, and -7C in Birmingham, forecasters said.
Kent Police are advising of "very poor visibility" and "hazardous" driving conditions across the county including the M25 and M20. In Hampshire, police said that although there was no snowfall overnight, freezing conditions are making the roads unsafe.
On Friday morning, Kent Police said that the M25, M26 and M2 are passable with care, but Operation Stack, the force's plan for major congestion on the M20, is in place, with traffic being diverted off the motorway at junction 11 on to the A20.
Only Eurotunnel freight traffic is being queued between junctions 11 and 12. All other freight will be diverted as other traffic.
Meanwhile, under-fire Transport Secretary Philip Hammond has warned train companies to keep stranded passengers better informed but said transport problems were inevitable as a blanket of snow and ice covers Britain.
Mr Hammond, who was told to "get a grip" after cancellations left thousands of people high and dry, said he had heard "far too many stories" about people being unable to obtain information about train services.
The minister's comments came as Britain endured another night of wintry weather with temperatures falling to -20C, but the easing of snow showers meant Gatwick Airport reopened on Friday morning.
On the train networks, some services were cancelled by line operators First TransPennine, First Capital, Cross Country, First Great Western and Northern Rail. Warnings of severe disruption were also given by London Overground, East Coast, East Midlands, First Hull and South West trains.