Scientists from Imperial College London predict rising summer temperatures will have a greater impact on the Health of Londoners than anywhere else in the country.
Researchers looked at temperature records and death rates for 2001 to 2010 to find out which districts in England and Wales experience the biggest effects from warm temperatures.
In the most vulnerable districts, in London and the southeast, the odds of dying from heart or lung causes increased by more than 10 per cent for every 1C rise in temperature.
Districts in the far north were much more resilient, seeing no increase in deaths at equivalent temperatures.
Across England and Wales as a whole, a summer that is 2C warmer than average would be expected to cause around 1,550 extra deaths, the study found.
Just over half would be in people aged over 85, and 62 per cent would be in women.
The effects of warm temperature were similar in urban and rural districts. The most vulnerable districts included deprived districts in London such as Hackney and Tower Hamlets, with the odds of dying more than doubling on very hot days like those of August 2003.
According to the man who led the study, Professor Majid Ezzati, from Imperial College London, more research into why there are regional differences is now required.