DRIVERS were heading off on the big Christmas getaway today as the freezing weather kept its grip on the country.
With many areas waking up to yet another icy morning, motorists heading home and out shopping faced one of the busiest driving days of the year.
Train travellers today had to contend with delays and cancellations.
A number of London to Leeds East Coast main line services were axed and some of the trains between the two cities will also be cancelled tomorrow.
First Great Western has to cancel some London to Cardiff services today, while there were also cancellations to some ScotRail services.
London commuter company First Capital Connect was running an amended timetable today, while Northern Rail had to cancel more than 30 trains.
Those using railways over the festive period will face some disruption from planned engineering work.
Work at Reading in Berkshire will affect Great Western services, while there will be disruption from work around Birmingham, and at Liverpool Street and Blackfriars stations in London.
Network Rail has promised that there will be more trains than over last Christmas and new year and that fewer replacement buses will have to run.
Edward Welsh, director of corporate affairs at the Association of Train Operating Companies said some operators would be reducing services today by up to 25%.
He told BBC Radio 4's Today programme: "Some train companies are running reduced services in some cases. Three train companies have quite significant reductions in their timetables, others are more minor."
Pressed on how significant the reductions would be, he replied: "It could be around the figure of 25%."
He added: "As of now, all routes are open, except for a small number of lines in Scotland."
Mr Welsh said he understood passengers' frustrations at yesterday's delays but said most services had got through: "There definitely were delays and cancellations and we understand people's frustrations, but actually the majority of services got through and most of them arrived on time."
He said the timetable reductions meant the remaining services could run more reliably.
The number of cars on the roads was expected to peak later this evening as people try and get home before Christmas Eve and out for some last-minute bargains.
The AA's Paul Watters said: "We are building up for a problematic day on the roads."
Passenger backlogs at airports and on the trains have begun to ease, but critics are rounding on the UK's inability to cope with wintry weather.
Much of the country saw temperatures fall below zero overnight, prompting widespread warnings for icy roads.
The majority of the UK should stay dry but cold today, with slight snow showers in northern and eastern parts of the country.
Weather-related troubles saw the motoring rescuers field an estimated 21,000 call-outs yesterday, and Mr Watters said: "We don't expect today to be any easier."
Heathrow - which has made headlines for days as massive amounts of flights were cancelled due to snow and ice - said it was expecting to operate 1,206 flights today, almost a full schedule.
After reopening its second runway on Tuesday, the gateway fulfilled two-thirds of its business yesterday but stressed passengers should not expect an immediate return to normality.
Mayor of London Boris Johnson said operator BAA had "very serious lessons" to learn from the chaos.
BMI chief executive Wolfgang Prock-Schauer also claimed the airport "did not have enough de-icing fluid" - something a Heathrow spokesman strenuously denied.
"It is categorically untrue that we have either run out of de-icer, failed to order enough de-icer or accepted de-icer supplies from the Government," the spokesman said.
Meanwhile under-fire BAA chief executive Colin Matthews announced he would forgo his annual bonus.
Mr Matthews said: "I have decided to give up my bonus for the current year. My focus is on keeping people moving and rebuilding confidence in Heathrow."
BAA would not reveal how much his bonus was.
And after cancelling more than 2,000 flights, British Airways said it hoped today and Christmas Eve would see it operate a full long-haul departure schedule from Heathrow. It will also operate a normal schedule at Gatwick and London City airports.
All airports continued to tell customers to check with their airline if their flight was operating.
Sean Tipton of the Association of British Travel Agents said: "The travel industry is very pleased that both Heathrow and Gatwick are returning to normal service.
"However, there will still be some delays and cancellations due to the many aircraft being out of position.
"Many package holidaymakers whose flights were cancelled over the weekend will now be jetting off on holiday due to their flights being rescheduled."
After the Eurostar was crippled, a company spokesman said it was running 90% of its service.
The travel improvement coincided with weather forecasters predicting relatively mild weather in the run up to Christmas Day.
The Highways Agency has completed, or suspended, a number of roadworks on England's motorways and major A roads over the Christmas and new year period.
But a number of works remain in place, including some on the M25 and also on a busy section of the M1 through Bedfordshire.
The RAC said city centres, retail parks and major shopping centres would be extremely busy today, as people looked for last minute pre-Christmas bargains to complete their festive shopping.
The RAC said that although many families were beginning their Christmas getaway today, traffic was likely to be busiest tomorrow (Christmas Eve).
RAC patrol ambassador of the year, Alan Wilcock said: "After all the recent bad weather and with Christmas being the busiest time of the year on the roads, we recommend that people double check their route before setting off to check for any problems and listen to traffic updates."
Simon Sheldon-Wilson, director of traffic management at the Highways Agency told the programme: "We entered this period better prepared. We ordered more salt than we have previously at this time of year.
"The roads are running very well at the moment. In general terms, the roads are running very well."
Transport company National Express said that 10am today was likely to be the busiest time on roads over Christmas.
The company has laid on 200 extra coaches for the festive period and was expecting to run 40% more coach services than usual today, carrying 50,000 people.
National Express said the next busiest day for travelling is likely to be next Monday.
Accidents and sheer weight of traffic led to congestion on a number of major roads today.
There were hold-ups on the A1 northbound near Washington and Birtley at a point south of Newcastle upon Tyne and also congestion on the A19 between the A1027 and A689 in north east England.
There were also tailbacks on the A1 near Newcastle upon Tyne and on the A419 north of Swindon in Wiltshire.
Heathrow operated around 90% of its flights today, with more than 200,000 people travelling.
But the west London airport warned that many planes and crews remained out of position, so there were still likely to be some delays and cancellations.
A Heathrow spokesman said: "We are extremely sorry for the disruption to people's journeys and we are working hard with airlines to return to a normal schedule."
British Airways, which is allowing anyone booked until December 31 to either rebook or get a refund, said it hoped to operate all its Heathrow long-haul services today and the "vast majority" of short-haul flights.
The Local Government Association (LGA) promised that gritters would be operating on Christmas Day.
Councillor Peter Box, chairman of the LGA's economy and transport board, said: "For the gritting teams who have been working tirelessly over the last month to keep our roads open, Christmas Day will be just like any other working day.
"We expect roads to be extra busy tonight with people making their way home to spend Christmas with their families. Highways teams will be doing everything in their power to clear the roads of snow and ice to ensure that people get home safely."