Thousands of passengers have been left stranded as airports struggle to cope with the weather The big freeze is likely to keep many thousands of families apart at Christmas.
Drivers have been warned not to go out on treacherous roads, flights have been cancelled and train services badly disrupted by the cold.
The AA and police have urged families to postpone celebrations until the roads are safer.
At least 16 people have died in the freeze, including two pensioners killed when a coach skidded on ice on an ungritted road in Cornwall.
Thick fog, snow and black ice are expected to hit major roads again today.
The Christmas getaway is normally one of the busiest times of the year, but the millions hoping to hit the road today are being warned: You'd be dicing with death.
The prospect of a lonely Christmas for many moved closer yesterday as rain showers froze almost instantly on already treacherous roads, making conditions lethal.
Temperatures are expected to stay near-freezing all day, so the ice will not melt.
Thousands of would-be air passengers were left stranded yesterday as airports struggled to cope with the weather.
Families arriving at airports including Heathrow, Gatwick and Luton faced a desperate race against time to make alternative travel arrangements as the snow, sleet and fog grounded dozens of flights.
A Ryanair plane carrying 129 people slid off an icy runway after landing at Prestwick Airport, near Glasgow. Luckily, noone was hurt.
Traffic was at a standstill both on Oxford Street and on the M6 yesterday as Britons prepared for ChristmasThe Met Office has issued warnings of 'widespread icy roads' for most of England, Scotland and Northern Ireland today.
Those expected to be worst affected by bad weather and heavy traffic include the M1, M4 and M11 out of London, the M6 junctions for Manchester and the Tyne Tunnel in the North-East.
Many of Britain's busiest roads were brought to a standstill yesterday by hundreds of collisions, including a 40-car pileup on the A35 Tolpuddle bypass near Bere Regis in Dorset where the road was described as an ice rink.
An AA spokesman said: 'We expect the roads to be treacherous in many parts of the country with lethal black ice.
'If possible, stay at home for Christmas where you will be safe. If you have planned to visit relatives or friends try to postpone Christmas for a day or two and celebrate it on Boxing Day or December 27 when the weather is expected to improve.
'Obviously, with Christmas almost upon us some people are going to take the risk to travel, but that could prove a very dangerous and expensive mistake.'
The scene of the coach crash near Penzance, Cornwall, which killed two women and injured 47 other passengers 
Ice escape: No one was hurt when a jet slid off the runway at Prestwick airport in GlasgowHampshire Police have advised motorists not to go out unless their journey is absolutely essential. After a string of crashes, Chief Superintendent Matthew Greening said: 'It seems a lot of people were not really aware of the dangerous conditions until they got out.'
I'm still waiting: Eurostar passengers queue at St Pancras station The Highways Agency, responsible for gritting motorways and major trunk roads, said it was closely monitoring conditions with continuous salt treatment on high-risk routes.
A spokesman said: 'We are experiencing localised problems across southern and south-west England as a result of rain showers falling on road surfaces that are already below freezing. Our service providers are re-salting roads, but driving conditions remain difficult.
'Drivers are advised, if they decide that they must travel, to take additional care, in particular leaving sufficient distance between vehicles so they can brake and stop safely.'
People hoping to travel by train are being warned about long delays in many areas.
The Southeastern train company was unable to run trains on some of its routes yesterday and could not provide a bus replacement service because of poor road conditions.
Travellers were already facing disruption over the holiday period from planned engineering works by Network Rail lasting until the New Year.
The continuing cold forced the budget airline easyJet, which cancelled 150 flights on Monday, to cancel another 50 yesterday from airports across the UK.
BA cancelled several flights to European cities including Paris, Zurich, Stockholm, Brussels and Amsterdam. Some passengers at Heathrow have spent more than 48 hours trying to get to their Christmas destinations.
Pensioners Terry and Pat Palmer, from Woking in Surrey, were supposed to go to Geneva on an easyjet flight from Gatwick on Tuesday morning. Mr Palmer, 68, said: 'When we got there we found it was cancelled, even though it didn't say so online before we left.
Red sky at night: The freezing weather may have caused chaos ahead of Christmas, but it has also made for some spectacular views, such as this one seen looking west from the River Earn in Perthshire 'Easyjet didn't give us an explanation, they just told us to get our money back and make our own alternative arrangements. We were put on a Heathrow flight by BA to Geneva but that was also cancelled this morning.' His 67-year-old wife added: 'We are spending Christmas with our children and grandchildren in Geneva.
'Our family from Stoke have made it from East Midlands Airport-so everyone is waiting on us. If we don't get there it would totally ruin Christmas for all of us.'
At St. Pancras there were once again long queues of passengers trying to board a skeleton Eurostar service.
The company is expecting to run only about two-thirds of its normal services today and warned people without tickets to stay away.
Weathermen say the freeze is likely to end tomorrow in the south of England but persist until Boxing Day in the north.
source: dailymail