Wintery weather is set to cause travel disruption as up to 10cm of snow falls in parts of Britain over the next 48 hours, forecasters have warned.
Snow has already begun to fall in Scotland and will slowly spread south today and overnight delivering a light dusting, but a heavier dump is expected to land over north Wales, central England and northern England on Monday.
Most of the areas will see between 2cm and 5cm settle while some areas such as Yorkshire will see up to 10cm settle.
Cold weather will take hold of all the UK, but southern England and Wales is likely to be spared snow.
It said: "This weather could increase the health risks to vulnerable patients and disrupt the delivery of services."
Nick Prebble, a forecaster for MeteoGroup, the weather division of the Press Association, said: "A lot of people will be waking up to snow in Scotland this morning and there will be a light dusting in north-east England and Yorkshire.
"The snow will spread south-eastwards throughout the course of the day reaching Manchester, and overnight much of England will have snow flurries.
"But it will be throughout Monday when the heaviest snow falls, affecting central and east England and northern Wales.
"Those areas will see between 2cm and 5cm by the end of the day, but there is the potential for up to 10cm locally.
"It will be quite disruptive throughout the day before it clears on Monday night.
"Temperatures will be noticeably cold for most of England, barely above one degree where the snow falls and around six degrees in western areas of England."
He added that the cold weather is likely to linger for the week with the possibility of more light snow flurries in central and eastern England.
"It's no surprise from looking at the weather reports that Amazon.co.uk customers are sensibly preparing by stocking up on snow shovels," said Xavier Garambois, vice president of EU retail.
"Sledging is undoubtedly the best thing about snow and, hopefully, a lot of fun will be had by all this weekend."
Tesco said its sales of shovels are up more than five times last week's levels and expects them to increase even further in the coming days.
Sales of cold-weather car products such as windscreen wash with anti-freeze and ice scrapers are already 25% higher than last week.
"It looks like many people are also looking forward to the lighter side of the snowfall. Tesco Direct has experienced a sudden surge in online interest in products including snow sledges, snow shoes and even a snowball blaster," a spokesman said.
"Online shoppers can use Click and Collect to order and pick up their purchases the next day in good time for the unusual weather conditions."
The AA has warned that 75% of drivers are not prepared for conditions on the roads, and urged drivers to carry an essential winter kit and check their cars before getting behind the wheel.
The RAC is expecting up to 56,000 breakdowns and widespread disruption. It has placed extra patrols on stand-by to help stranded motorists and said call-outs are expected to rise by 20% or more.
The Highways Agency has said it is "well prepared" for winter conditions.
A spokeswoman said: "We have a fleet of 500 state-of-the-art winter vehicles on standby, supported by tried-and-tested winter resilience plans.
"We have reviewed salt stock levels and taken action where needed to enhance our resilience and we have again established a reserve salt stock to help ensure that there is enough salt to deal with severe winter.
"Our roads will be treated whenever there is a risk of ice or snow. However, even when roads have been treated, drivers should still take care, especially on stretches where the local road layout or landscape means there could be a greater risk of ice forming."