Who will live the longest?

Japan - 90.91 years France - 87.81 Canada - 85.26 UK - 83.79 Germany - 83.12 US - 82.91

It is already well known that there will be a greater proportion of elderly people in the population in the future.

The so-called "baby-boomer" generation will enter its 60s over the next decade, so the effect will become more pronounced.

However, the Californian demographic experts, led by Dr Shripad Tuljapurkar, suggest that mortality rates from disease in the G7 countries - Canada, France, Germany, Japan, the UK and US will fall at a higher rate than projected by past studies.

Japanese longevity

This translates to, at worst, an extra year of life beyond current estimates in countries such as the UK - and in some countries, such as Japan, an extra eight years on average.

Canada also fares well, with an extra three and a half years, as does France, with an extra four and a half years.

Even small shifts in life expectancy can have a marked effect on population sizes, so the finding, reported in the journal Nature, could be highly significant to those responsible for planning services for the elderly in the future.

A spokesman for Age Concern said: "Present trends do not suggest any expansion in NHS and other state provision for older people.

"The study fears a tightening of eligibility for state care with the consequence of those with other than extremely urgent needs being left to fend for themselves."

Living longer may not be completely good news, however - a recent government study suggested that while people were living longer, the number of years of ill-health suffered also increased.