Up to 20,000 cold-related deaths could be prevented every year if there is significant climate change in the UK.

Warmer, wetter, winters would be good news for the elderly, and for the NHS.

However, a Department of Health backed report says the downside would be thousands more deaths from skin cancer and heatwaves, and many more cases of food poisoning and tropical diseases such as malaria.

Some scientists believe that average temperatures could rise by as much as two degrees centigrade over the next 50 years.

A shift of this magnitude would radically alter the UK's weather patterns, increasing not only the incidence of gales and floods, but also extraordinary heatwaves, which might happen once every few years.

The report warns that while an estimated 20,000 people a year would not fall prey to winter-related illness such as flu, an extra 2,800 a year would die because of the rise in temperature.

The report says: "By 2050, the climate of the UK may be such that indigenous malaria could become reestablished, but this is unlikely to present a major problem."

Skin cancer

The change could lead to an extra 30,000 cases of skin cancers each year, though the majority would be cured.

However, the Expert Group on Climate Change, which wrote the report, said the NHS was likely to cope well with the extra cancers, and an estimated 10,000 extra cases of food poisoning each year caused by food going rotten in the higher temperatures.

But it warns that coastal defences and disaster responses should be beefed up.

"Should such an event occur, and climate change may well increase the risk of such an event occurring, local NHS resources would be likely to be overwhelmed."