More than 2,000 people may have died because of the August heatwave in which temperatures stayed over 30C (86F) for ten consecutive days.
The death toll in England and Wales between 4 and 13 August reached 15,187, which is 2,045 more than the average for the previous five years, the Office for National Statistics said.
Researchers found that the peak was reached on 11 August the day after records were broken and the temperature topped 37.8C (100F) for the first time. On that day 1,691 people died, 363 more than the average.
Statisticians said the figures did not prove the extra deaths were because of the heat but health experts said it was likely. The figures for Scotland and Northern Ireland were not included. "There's a very convincing story that in fact the climate did cause excess deaths for a short period," said Dr David Pencheon of the Institute of Public Health at Cambridge University.
"Climate does influence the exact day of death, but when you even things out, it tends to bring the deaths that are about to happen in the next two or three months all into a few weeks or so.
"There's no evidence that it kills off people who were not going to die in the next, say, two or three months," he said. "A lot of people at any one time are close to death. You only need a slight change for it to suddenly bunch together."
The study was triggered by the high death toll in France where almost 15,000 people, mostly over the age of 75, died during August when temperatures topped 40C for several days. Half the victims are believed to have died in old people's homes, many operating with reduced staff during the August holiday period.
President Jacques Chirac has admitted shortcomings in the country's highly prized health system and pledged more money for emergency services. The head of the health service, Lucien Abenhaim, resigned over the scandal.
In the UK, however, the Department of Health said that hospitals had not experienced any significant problems. Ambulance services had extra calls with more people going to casualty departments, but they were able to cope with the extra numbers, the department said. Undertakers eported a busier August than for recent years.
During the sustained period of hot weather, that led to chaos on the country's rail network as well as bumper profits for ice cream makers, the highest recorded temperature was on 10 August at Brogdale, near Faversham, Kent, with 38.5C (101.3F).
London, the East of England and the South East, which experienced the highest temperatures, had 6,044 deaths between 4 and 13 August - 40 per cent of the national total.
Clare Griffiths, a senior mortality researcher at the Office for National Statistics, said that after a peak, deaths were likely to dip lower than expected and then return to average levels.
She said it was too soon to see whether that was true following the August heat wave. A 20-year study which examined deaths and temperatures from 1976 to 1996 in London found that deaths started to rise once the temperature reached 19C (66F).
Previously, the biggest increase was in the 15-day heatwave in July and August 1976, when the extra deaths were twice those during any other hot spell.
Over the month of August, there were an estimated 1,500 extra deaths compared with the previous five years, but deaths in July were 750 below average.
Liberal Democrat health spokesman Dr Evan Harris said: "It is essential that ministers introduce the right public health measures to prevent excess deaths. People need to receive more information on what they should do to keep healthy."
Despite the extra deaths from the heat, cold weather claims more lives and even a mild winter can cause 4,000 extra deaths. In a bad year the excess toll may rise to 25,000.Reuse content