A woman walking her dog following a light dusting of snow at Tan Hill in North Yorkshire on Sunday.
Sub-zero temperatures are expected to sweep across Britain this week after the first cold snap of the year, prompting warnings that vulnerable people should prepare for a freezing winter.
The chilly weather coincides with the launch of a major NHS campaign urging people with long-term health conditions and the over-65s to take action in an effort to reduce the 25,000 extra deaths that occur each winter.
Prof Keith Willett, medical director for acute care at NHS England, said: It is vital that the most vulnerable people take preventative steps to keep healthy and stay well. We have a high number of A&E attendances over this time that are due to issues that could have been avoided had people sought advice at the first sign of illness.
The Stay Well This Winter campaign will use TV, radio and social media to encourage people to wrap up warm and consult a pharmacist as soon as they feel unwell rather than waiting.
It also encourages people, particularly those with long-term illnesses or mobility problems, to heat their homes to at least 18C (65F) and to check on friends and neighbours who may be vulnerable.
Prof Paul Cosford, director for health protection at Public Health England, said: “With winter on the way, now is a good time to make sure you, and those you know who may be particularly at risk from the cold, are as prepared as possible. If you qualify for the free flu jab, get it now.
“Also remember that eating a healthy, balanced diet and that staying physically active can keep you healthy.”
He added that assistance with heating costs is available to those who might need it. “There are a variety of ways you can apply for help to keep your house warm, such as winter fuel payments, warm home discounts and cold weather payments. If you meet the criteria, register for priority service with your energy and water suppliers.
“Try to maintain indoor temperatures to at least 18°C (65°F), particularly if you find it hard to get around, have a long-term illness or are 65 or over. You may prefer your living room to be slightly warmer,” he said.
Cold weather increases the risk of heart failure, kidney disease, stroke or dementia, as well as making heart attacks and strokes more likely.
For each degree centigrade the temperature falls below five degrees, there is a 10% increase in the number of older people seeing their GP about breathing problems, a 0.8% increase in emergency hospital admissions, and a 3.4% increase in deaths, research shows.
The UK shivered through a chilly Bonfire night, as temperatures fell below freezing in places, snow fell on higher ground and biting winds made conditions feel colder. On Sunday night temperatures outside the south-east were expected to fall below zero across much of the country.
Tom Crocker, a forecaster at the Met Office, said the cold snap is likely to last: “The forecast over the next few days is staying rather chilly.”
The BBC expects Monday night to be the coldest so far this winter, leading to widespread frost. Crocker expected Monday to be bright but cold across much of the country.
“Tuesday looks like being another relatively bright day, but we have got quite persistent rain moving in from the west on Tuesday afternoon,” he said. Snow is expected to be widespread on higher ground.
The precipitation is likely to make Tuesday night warmer, he said, although it is still likely to be below freezing in rural areas.
“It will be turning a little bit milder towards the end of the week, but still chilly and unsettled,” Crocker said. Temperatures are expected to move into the low double figures, especially in the south.