More ice, snow and freezing temperatures are set to wreak further havoc on the roads as millions of people are being warned of stressful Christmas Eve travel.
With heavy snow fall and temperatures plunging below zero overnight, travellers in northern Britain face the worst disruption.
People across the country are being urged to leave more time for their journeys as widespread icy roads and more delays at airports are predicted on one of the year's busiest travel days.
The highlands of Scotland registered temperatures as low as minus 15C (5F), while Edinburgh saw a minus 11C (12F) on Wednesday night.
Southern England was comparatively warmer on Thursday, ranging from freezing 0C (32F) to 3C (37F).
The Met Office has issued severe weather warnings of "widespread icy roads" for virtually all of England, Wales and Northern Ireland.
The Highways Agency, which is responsible for gritting motorways and major trunk roads in England, said it was monitoring conditions and administering salt treatment on high-risk routes.
John Hutchinson, a forecaster with MeteoGroup, the weather division of the Press Association, said: "The coldest areas will be from Cumbria northwards.
"In central and southern England there are showers about - with some pretty heavy bursts."
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