Average life expectancy for women in England and Wales could be approaching 90 by 2030. Men are also set to live longer than official estimates predict as the historic gender gap narrows.
But life span differences between better and worse off communities are likely to increase to levels that mirror those dividing Western and developing countries, say the researchers.
The study, based on Office for National Statistics data combined with advanced mathematical modelling, suggests that average life expectancy for women will rise from 83.3 in 2012 to 87.6 in 2030.
For men, it is predicted to increase from 79.5 to 85.7 over the same period.
The forecasts for 2030 are higher than those issued by the Office for National Statistics by 2.4 years for men and one year for women.
But the upward trend masks significant regional differences, the research shows.
By 2030, people in affluent southern England and well-off districts of London are expected to be living more than eight years longer than those in northern urban centres such as Blackpool, Liverpool and Manchester, as well as South Wales.
That is equivalent to the difference in life expectancy between the UK and Sri Lanka or Vietnam.
Within London, a stark survival gap was seen between the haves and have-nots. In 2012, the wealthy residents of Kensington and Chelsea lived on average five or six years longer than their poorer neighbours in Barking, Dagenham and Tower Hamlets.
Lead scientist Professor Majid Ezzati, from the School of Public Health at Imperial College London, said: "The bigger gains in life expectancy we predict will mean pensions will have larger payouts, and health and social services will have to serve an older population than currently planned.
"We also forecast rising inequalities, with bigger increases in lifespan for people in affluent areas than those in disadvantaged areas. This means wealthy people will benefit more from health and social services than poor people, and therefore should be prepared to pay its costs through higher taxes."
The research, published in The Lancet medical journal, drew on death rate and population data for 375 local authority districts in England and Wales dating back to the 1980s.
Five mathematical models were constructed whose accuracy was tested by seeing how well they predicted actual life expectancy trends from 2002 to 2012. The best model was then used to make forecasts to 2030.
"Our methods better reflect how longevity is changing than those currently used, and our forecasts are more accurate," said Prof Ezzati.
He called on politicians gearing up for the General Election to call an end to austerity.
"Such policies will, at best, cause the rising inequality trends to continue, and could well worsen them because their adverse effects are particularly large on children and working age people, and on more disadvantaged social groups and communities, with signs of poverty already emerging," he said.
NHS reforms giving local government more control over health and social care and increasing the role of the private sector was likely to "weaken health systems and worsen inequalities in health care access and quality".
Professor Sir Michael Marmot, director of the Institute of Health Equity at University College London, said: "This study predicts that inequalities in life expectancy are likely to increase by 2030.
"These inequalities vary with deprivation of district along the social gradient: the more deprived, the shorter the predicted life expectancy. There are even bigger variations within district - bigger in deprived districts than in more affluent ones. More deprived communities are more vulnerable to the causes of inequalities in health.
"The implication is that people of higher socioeconomic position will benefit from health and other services for longer than more deprived people. Is this fair?
"A key question that the research did not address is healthy life expectancy. Will people have longer healthy lives, or more sickness?"