Britain could be facing its hottest Christmas EVER as a dust storm from the Sahara brings killer smog and “blood rain”.
Asthmatics have been warned to stay indoors – as have people suffering other health problems.
A smog alert has been issued for much of the UK as the African sand smothered the land.
And Britain could face the warmest December for 70 years as temperatures soar to 16C – 10C higher than the average for this time of year.
The weather has been so mild that daffodils have been begun flowering as far north as Chester – and hopes of a white Christmas are vanishing.
It has been so warm that punters were out on the River Cam in Cambridge, which is normally iced over by now, wearing T-shirts.
Experts warned those with chest problems to avoid strenuous exercise.
Asthma UK’s Andrew Proctor said: “People with asthma must take extra care this week.
“We are facing a perfect storm of asthma triggers, with air pollution and weather changes increasing the risk of potentially fatal asthma attacks.”
Defra added: “There is a risk of moderate or high levels of air pollution due to Saharan dust.
“Those with lung or heart problems should reduce strenuous physical exertion, particularly outdoors.”
A mix of desert sand and downpours could spark a deluge of “blood rain” – where it gets into the water droplets – leaving a fine layer of red dust.
Satellite images show the mass of fog swirling in the Atlantic ocean.
The worst affected areas will be Central and Eastern England where a level seven warning was issued. But London, the South East and the West Country are also on smog alert.