Christmas shoppers and motorists have been warned to expect treacherous weather conditions , with ice warnings in place for the entire country as the cold snap continues.
Flights were delayed at Liverpool, Manchester and Luton airports because of snow. Forecasters predict snowy showers will strike western areas and the far north of Scotland on Sunday before conditions start to ease on Monday morning.
Meanwhile, lower-than-typical average temperatures are set to continue, with the mercury likely to fall to –1C in the south of England and Wales, –2C in Yorkshire, –4C in the Borders and –6C in Scotland.
Clare Allen, forecaster for MeteoGroup, said: "The rest of the country is expected to remain very cold, with widespread frosts and everywhere below zero, apart from the south-west."
The AA reiterated a warning to drivers to consider delaying their journeys if the weather deteriorates. A spokesman said: "Road users are reminded to plan for their journeys before setting out, checking the forecast and road conditions and leaving extra time if travel conditions are poor. They are also advised to be prepared and carry warm clothing and an emergency pack, which includes food and water, boots, de-icer, a torch and a shovel in case of snow."
The Highways Agency remained confident that it could handle the cold weather, announcing that it had 500 state-of-the-art winter vehicles on standby and enough salt to deal with severe conditions.
However, the cold snap could mean bad news for retailers, who have described this weekend as "make or break" for sales after weeks of price cutting have failed to attract as many customers as hoped.
Jace Tyrrell, from the New West End Company, which represents Oxford Street and Regent Street in London, two of Britain's busiest shopping streets, said: "For many retailers this is the make-or-break weekend, especially for the fashion and technology sectors."
However, more than 250,000 shoppers were expected to visit Bluewater shopping centre in Greenhithe, Kent, over the weekend, and by midday on Saturday the centre's 13,000 parking spaces were 80% full.
Nationwide, more than 11 million people were expected to spend more than £1bn at £1.5m a minute , according to a report by the shopping comparison website Kelkoo.
Unlike the heavy snowfalls of the two previous Christmas periods, the country's first truly wintry weekend of this season is likely to be replaced by milder temperatures.
Early parts of this week will, according to the Met Office, see temperatures rising again, an outlook that will brighten the hopes of retailers.
Ladbrokes has slashed the odds of a white Christmas. It now estimates a 3-1 chance that London will have snow on 25 December, while Edinburgh and Glasgow have had their odds trimmed to 9-4. The odds are lowest in Lerwick, Shetland, at 6-4, followed by Aviemore, in the Cairngorms, at 7-4. Tyne Bridge in Newcastle is, jointly, the most likely place in England for snow to fall next Sunday, also with odds of 3-1.
However, the milder temperatures that have been forecast, allied to confirmation that most major transport networks are expected to function normally until late on Christmas Eve, will soften fears that the chaos of recent Christmas getaways will be repeated.
A quarter of the population are expected to take to the roads over the festive season and motorists have been urged to take extra care on the roads.
