It predicts a “heavy financial toll” as the key Christmas shopping period is disrupted, entertaining becomes difficult and supply chains break down.

The insurance company was previously known as Royal Sun Alliance but, like Britain itself, waved goodbye to the sun long ago – and it says the consequences for the economy of a prolonged cold spell could be dire.

RSA director David Greaves said: “This cold front couldn’t come at a worse time for the UK. Bad weather in the run up to Christmas will have a major impact on the UK’s economy and could lead to significant losses for already struggling businesses.

“We’re due to see a rush of sales in December ahead of the VAT rise in the New Year, and many retailers are relying on these sales to see them through the traditionally quiet post-January sales period.

“If we lose just one fifth of our daily GDP through companies not being able to open and people cancelling spending plans on events and shopping we’re looking at about £1.2bn every working day.

“If the weather continues for the next two weeks, as the Met Office is predicting, this figure will quickly spiral to more than £12bn, dwarfing the hit we took in January this year.”

But there was good news for shopping websites, as RSA said predicted customers could be “forced off the high street and towards online retailers”.

“One thing that will be new on Monday is the wind,” says BBC weather forecaster Liam Dutton. “It will be really quite strong, so significant wind chill will be an issue. Even where there isn’t new snow, what’s there already will be blown about and roads that have been cleared could be covered up again.”

Rock salt suppliers are quoted warning of impending shortages – one reports record sales, difficulties in finding supplies to import despite trying countries like Egypt and Russia, and serious problems by the end of the year.

Sky’s weather presenter Isobel Lang warns of “another exceptionally cold night” while Michael Dukes – a weatherman from wire service PA who is quoted in many places including Sky, The Sun, and The Independent – says the temperatures in some parts of the country are “ridiculously low” and like being in the middle of Scandinavia.

Still more concerned with the Cancun climate change talks, the Indy nevertheless finds space to excitedly declare “cold weather records tumbled like snowflakes at the weekend as Arctic conditions gripped Britain”.

The paper also highlights warnings from police and motoring organisations that thieves are targeting cars left with their engines running to warm up while their owners stay out of sight indoors.

The Telegraph leads with airport closures at Edinburgh and Derry before moving on to the commuter problems, and also gives a shout-out to the ubiquitous Mr Dukes.

And the Daily Mail tops the unofficial competition to roll out the most hackneyed stock phrases – in its headline and first three paragraphs it manages “mayhem Monday”, “commuter chaos”, “big freeze”, “Siberian blast”, blanketed swathes of the country and plunging mercury.

It also reports on fears from the British Trust for Ornithology and RSPB that robins and other small garden birds are being hit hard by the weather. Trust spokesman Paul Stancliffe is quoted saying: “Although we think of robins in the winter amongst the snow, they actually do badly in those conditions.”

The BBC reports that an RAF rescue helicopter in south Wales had to try four hospitals before it could find one where the snow was light enough to allow it to land with two people rescued from the Brecon Beacons.

And it quotes its weather forecaster Peter Gibbs as saying: “By Monday into Tuesday almost anywhere down the eastern side of the country could be seeing snow, possibly into the Midlands.”

For those not already sick of the snow, it has a page of photos sent in by readers – snowscapes and street scenes and nature shots that are appealing now, but will certainly have lost their sparkle this time next week.

ITN is less cautious than the Beeb – while Auntie doesn’t like to predict more than a week ahead, its independent rival boldly (and rather depressingly) says there’s weeks of freezing weather to come.

It says police in affected areas are urging people to stay indoors, a warning also passed on by Sky.

The Murdoch channel follows the BBC’s line on how long the weather will last for, saying “several more days”, and quotes the AA as saying it had dealt with 10,400 breakdowns by mid afternoon, up 80 per cent up on a normal Saturday in November.

In the newspapers, The Sun cracks open its bumper book of weather cliches, trotting out the dependable “snow chaos”, “big chill” and “Arctic blast” lines. It predicts up to “TWO WEEKS” of cold.

Not wanting to be outdone, the Mirror opts for a “TWO-MONTH big freeze“. All it can find to follow it up with, though, is a half-hearted “travel chaos” and soon it’s reduced to reporting a Tweet by footballer Robbie Savage: “Today is the day when men get ­separated from big girls blouses who will wear gloves, leggins and snoodes!!! Be a man!”

The Independent is far more interested in the Cancun climate change talks than in the weather here, while the Guardian quotes a Met Office forecaster warning “there will be few places in the British Isles that will escape”. Its AA spokesperson says breakdowns are only up 40 per cent.

Predictably, the comments section of the Daily Mail story consists of huffing and puffing about today’s winters being far easier than they were years ago, when the police weren’t so liberal and soft and didn’t tell people to stay at home. Oh – and, of course, how this proves global warming is a sham.