Until 2012, when London stages the summer Olympic Games, the odds of thousands dying in summer heat each year will be 1 in 40, the report said, and thousands more could die each year as a result of other effects of global warming and air pollution.

"In terms of conventional thinking about risks to health, a risk of 1 in 40 is high," the report said.

Tens of thousands died across Europe in a heat wave during the summer of 2003, including over 14,000 people in France, but so far people living in Britain have coped with rising temperatures.

Although more summer deaths are expected, fewer people will die in Britain as a result of cold winter weather, as the world warms up because of rising carbon emissions from human activity.

The report, an update of a 2002 study, was re-issued on the same day London's mayor said owners of the most polluting cars will have to pay 25 pounds ($48.77) a day to drive them in the city centre in ameasure to cut down on carbon emissions.