Britain will be buried by the worst blizzards in almost a century in the coming days - as 12 inches of snow and 60mph-plus winds create 6ft snowdrifts and cause transport chaos.
Forecasters said up to a foot of snow will be dumped across Scotland, northern and western England from tomorrow morning, with several inches in the south.
Gale-force winds will create 6ft snowdrifts expected to shut dozens of main roads and threaten railway line closures - likely to lead to widespread school closures and millions struggling to and from work.
Forecasters said the blizzards will be more serious than an infamous blizzard in the cold 1962-63 winter and the worst to hit Britain since 1927.
Then, a 12-hour blizzard on Christmas Day night left 20ft snowdrifts across the south and south-east, with villages cut off for a week and supplied with food by air-drop.
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The Met Office has issued nationwide extreme weather warnings for snow and icy roads for the next two days, with Scotland, the north and west put on 'amber alert' - the second most-serious status, meaning 'be prepared'.
Government’s forecasters predicted up to 20cm of snow as well as gales or near-gale force winds nationwide, with wind speeds peaking at 55mph in Cornwall, 46mph in Lancashire and 62mph in Aberdeenshire.
The Met Office said temperatures will remain sub-zero everywhere in the UK bar the west coast during Friday daytime, while -15C nights will feel as cold as a scarcely-bearable -20C due to the Arctic winds.
The south is also at risk of a freak 12inch-plus snowfall on Sunday or Monday if moist continental air collides with cold air over Britain. Forecasters said 4ft drifts would result if this happens.
Netweather forecaster Ian Michaelwhite said: 'Through Thursday and into Friday, there will be up to a foot of snow in Scotland and northern and western England, with strong winds causing very severe drifting up to 6ft in height.
'There is also the chance moist air from across the Channel will hit cold air and cause extreme snowfall in the south over the weekend and into next week.
'There could be more than a foot of snow and 4ft drifts, caused by winds which are strong but not as serious as winds expected to cause 6ft drifts in the north.
'The most recent weather event comparable to what we are about to see is the famous Christmas Day blizzard of 1927.'
Charles Powell, a forecaster for the Met Office, said: 'We have got early warnings out for Thursday and Friday. Whereas a couple of weeks ago the main risk was in the eastern part of the country, this time the western side is most at risk.
'We are fairly certain that the western side will see some snowfall.'
Mr Powell said the snow would be 'quite significant' and could cause disruption.
Bookies have already slashed their odds of a white Christmas, and Mr Powell said it could be a while before we get a break from the chilly conditions.
'There is no real sign next week or the Christmas period of it warming up. It could well stay cold into the start of the New Year,' he added.
See also: Storm warning: Heaviest snow fall of the winter on the way
- Manchester Evening News
Snow set to send Britain back into deep freeze
- Channel4 News
UK fears worst winter weather since 1963
- The Guardian.
Transport secretary calls summit as Met Office predicts return of icy temperatures, further snow and transport disruption.
Icebound birds fell out of the sky, the sea froze and the third round of the FA Cup took 66 days to complete. These were the consequences of Britain's last truly Arctic season, in 1963, and the country may be facing it again in the next few weeks.
Forecasters are cautious about predicting a repeat of that cold spring. But the chaos of two weeks ago led the transport secretary, Philip Hammond, to call a national summit of government leaders today which sanctioned the purchase of 250,000 more tonnes of road salt.
It also agreed immediate distribution to councils hit by the new band of snow, from a national stockpile that has taken shipments from as far away as Peru.
Light snow is expected to dust much of the United Kingdom tomorrow , with temperatures plunging from the last week's "phoney thaw". Heavier falls are forecast for Friday in Scotland, northern England, parts of Cornwall, the North Sea coast as far as Suffolk, and the east coast of England and Wales.
The Met Office predicts icy temperatures next week, with "further snow, widespread ice, and severe overnight frosts likely in most parts of the country".
The longer-range forecast predicts that "unsettled and wintry weather will continue across the north of the country into the following week, while temperatures overall remain cold with further snowfall likely in places, especially eastern areas".
Hammond organised a national ring-round of transport operators to check on progress with avoiding a repeat of the road and rail delays and closure of Gatwick airport. "We entered this winter better prepared than last year," he claimed. "However, much of the country has been hit unusually early by severe weather."
Businesses have also clamoured for "effective and resilient measures" to avoid further damage to the economic recovery, which took an estimated hit of £4.8bn in the late November snow, according to insurers. The company RSA warned that similar disruption in the coming freeze could nearly triple that to £13bn, compounded if the last nine days of Christmas shopping were hit.
The Federation of Small Businesses echoed that warning. Its chair, John Walker, said: "We were disappointed that we still haven't learnt the lessons from previous bad weather and that the country yet again ground to a halt."
The Met Office said it was too early to warn of another 1963, despite December's unusual cold, the worst for 30 years. The current 30-day Met Office forecast suggest continuing cold, but with signs of warmer weather pushing in from the south towards the middle of January.
The RSPB called for community action on behalf of owls, which are vulnerable to starvation in freezing weather. Members of the public are encouraged to report sick or injured owls to a wildlife rescue centre. Quick action could save the life of a starving bird, it said.