The NHS is bracing itself for further strain on services as temperatures plummet and ice warnings are put in place this weekend.
The Met Office has issued a yellow warning for icy conditions on Friday night and into Saturday morning for parts of the north-east of England and Scotland, and in Cornwall, Devon and Somerset.
Temperatures are then set to fall on Saturday night due to “cold air and clear skies”, a Met Office spokesman said.
NHS England urged people to stock up on medicines, check on vulnerable or elderly neighbours and get the flu jab, after winter pressures put strain on the health service.
The comments came after it emerged that tens of thousands of planned operations could be delayed for at least a month, as the norovirus and rise in flu levels put pressure on hospitals.
A spokesman said: “Freezing conditions are forecast in some areas and evidence shows that the risk of heart attacks, strokes and other serious breathing problems increases as temperatures plummet.”
He added that two-and-a-half times as many flu sufferers have been admitted to hospital than at this point last year, with parts of France reporting being “on the brink of a flu ‘epidemic'”.
And Dr Nick Scriven, president of the Society for Acute Medicine, said a “real crisis” had developed since New Year’s Eve.
He said: “There has been debate as to what constitutes a crisis but to all those working at the front door the last four days has definitely been at that level.
“The temperature is set to drop again and looks like it will be below the 5C mark, which statistics show means more illness and more hospital attendances to come.”
He added that while some of the claims by medics had been “overzealous and hyperbolic”, he urged the Government to listen to doctors’ concerns and act on them.
The Met Office said that across parts of Scotland, temperatures overnight on Saturday could fall to as low as minus 10C (14F), which is much colder than average for the time of year.
However, the weekend will be drier and brighter than earlier in the week when high winds swept across the country.
Wind warnings were put in place in England and Wales on Thursday, with gusts as high as 77mph recorded in High Bradfield, Yorkshire.
Bookmaker Ladbrokes gave odds of 5/4 that this will be the coldest January on record.