An urgent health warning has been issued to pensioners and those with weakened immune systems as the UK braces for a bitter cold snap that is set to last for nearly two weeks. The UK Health Security Agency (UKHSA) has cold-weather health alerts as forecasters have warned that the mercury could drop to as low as -14C in the next fortnight.

The alerts are designed to protect those most at risk from cold-related illness, particularly older people, who could be more vulnerable to the effects of prolonged exposure to the cold. Health officials warn that cold weather can significantly increase the risk of respiratory illnesses, falls and can even increase the risk of blood clots, which could lead to heart attacks or strokes - especially among people over 65 or those with long-term health conditions.

Even moderately cold indoor temperatures can be dangerous, with the UKHSA advising that homes should be heated to at least 18C, particularly in rooms where older people spend most of their time.

The warning comes as the weather forecasts point to a sustained cold snap, with the beginning of January seeing daytime temperatures barely rise above 0C.

Icy pavements and untreated roads also raise the risk of slips and falls, another major concern for older adults during cold spells.

Two regions have been named as being particularly at risk, with amber warnings being issued until 12pm on January 5 in the North East and North West.

Dr Agostinho Sousa, the UKHSA head of extreme events and health protection, called on people to look after each other during the harsh conditions.

Speaking to The Guardian, he added: "The forecasted temperatures can have a serious impact on the health of some people, particularly for individuals over the age of 65 and those with pre-existing conditions."

His comments come as the Met Office has also issued a snow and ice weather warning for New Year's Day in areas of Scotland, marking the first weather alert of 2026.

Looking ahead to January, their forecast for January 2 until January 11 said: "Northerly winds will bring a spell of very cold, wintry conditions to much of, if not all of the UK, through at least the early part of this period.

"These will bring snow showers to areas that are exposed to onshore winds. Subtle day-to-day changes in wind direction will change the places most exposed to the showers, but where they occur, some significant accumulations of snow are likely.

"There are likely to be some more coherent bands of sleet and snow working south, and these may bring a risk of more prolonged and widespread wintry precipitation affecting some inland areas.

"Things become less certain by the second week of January; however, it's possible the cold conditions may persist with an ongoing risk of winter hazards across much of the UK."