Most babies born in Britain will live to 100

Most babies born in Britain today will live past the age of 100, scientists say. Life expectancy soared by more than 30 years in richer nations during the 20th century and shows no sign of slowing. It has risen steadily, by three months every year, for the past 160 years, and there is no reason to think it has hit a limit.

In Japan, female life expectancy at birth reached 86 in 2007, surpassing what was thought to to the human limit of 85, as assessed by scientists as recently as 1980.

Researchers say that we are living better for longer, and spending fewer of our extra years disabled and dependent on others. In the early part of the last century, improvements in infant and child survival contributed most to growing life expectancy, but since the 1950s, the biggest gains have been in the over-80s, who now have more than twice the chance of surviving to be 90.

After examining trends in life expectancy across the developed world, Professor Kaare Christensen and colleagues from the Danish Ageing Research Centre at the University of Southern Denmark said: "The linear increase in record life expectancy for more than 165 years does not suggest a looming limit to human lifespan. If life expectancy were approaching a limit, some deceleration of progress would probably occur. Continued progress in the longest-living populations suggests we are not close to a limit, and further rises in life expectancy seem likely."

What worries most people about ageing is losing their faculties and the ability to perform the daily tasks of living – feeding, dressing, bathing and getting around. But despite increases in cancer and chronic conditions such as diabetes and arthritis, disability has been falling. This apparent paradox is explained by earlier diagnosis and improved treatments which have rendered these conditions less disabling. In the future, more of us will fall ill, but the illnesses will affect us less.

However, there are large differences between countries in healthy life expectancy beyond 65 – that is, years spent without disability – and the UK performs poorly. While healthy life expectancy is rising among both sexes in Italy and Belgium, and among men in Germany, Austria and Finland and among women in Sweden, in the UK it is stagnating among women and falling among men.

"Progress towards improvement of health is likely to depend on public health efforts. For example, to combat smoking, obesity, low levels of exercise, poor diets and excess drinking, and to provide improved living conditions and care for elderly people with several ailments," they say.

The authors proposed a radical strategy for dealing with the financial and social challenges posed by the growing elderly population: encouraging people to work shorter weeks for a longer period of their lives. Most governments, they said, were already raising the retirement age.

"The 20th century was a century of redistribution of income. The 21st century could be a century of redistribution of work. Redistribution would spread work more evenly across populations and over the ages of life. Individuals could combine work, education, leisure and child-rearing in varying amounts at different ages. Preliminary evidence suggests that shortened working weeks over extended working lives might further contribute to increases in life expectancy and health," the study said.

"Very long lives are not the distant privilege of remote generations – very long lives are the probable destiny of most people alive now in developed nations," the scientists concluded.