A leading health expert is calling for an "urgent investigation" as improvements in life expectancy has almost "ground to a halt".

Life expectancy has been increasing for years but new data shows that it has levelled-off since 2010.

University College London professor Sir Michael Marmot said the stagnation was unexpected and he was "deeply concerned".

"I would say it is a matter of urgency to try and examine why this has happened - it is not inevitable that it should have levelled off," said the professor.

He said he could not draw conclusions as to why rises in life expectancy have faltered but raised concerns about "miserly" health and social care spending.

Credit: PA

"I am deeply concerned that if we do not fund health care and social care adequately people will lead much worse lives," he said.

"Whether that translates into an increase in mortality or a failure of mortality to go down, I don't know."

The professor's concerns about a possible link between austerity and life expectancy were dismissed by the government.

The Department of Health said it was continuing to invest to "ensure our ageing population is well cared for".

The new analysis shows that the increase in the rate of life expectancy had fallen by almost half since 2010.

Historically, improvements in life expectancy at birth had been around a one year increase every five years for women and every three and a half years for men.

But since 2010 this has slowed to a one year increase every 10 years for women and every six years for men, new analysis has shown.

Annual change in life expectancy for men and women. Credit: PA

The professor added that spending on "social expenditure is among the most miserly of Western European countries and our spending on health care is miserly".

He also warned that without "appropriate" funding of social care and the NHS, the quality of older people's lives and "maybe the length of life too" would suffer.

Another factor that could have played a part in the slowing of life expectancy could be dementia, said the professor.

Sir Michael pointed out that the leading cause of death among the elderly is now dementia and Alzheimer's.

"Dementia on the death certificate is the tip of the iceberg. If people are dying of dementia that means there is a lot of people living with dementia."

"Our spend on healthcare is going down, our spend on adult social care is going down and all the indicators suggest that the need is going up. It is not a good combination."

"We see the rise in dementia which is very troubling and that will require an increase in health and care spending and that's not happening."

Alzheimer's Society chief executive Jeremy Hughes said austerity was having an impact on the health of people.

"Too often we hear the consequences of inadequate, underfunded care - our investigation last year revealed people with dementia left in soiled sheets, becoming ill after eating out of date food, and ending up in costly hospital or care home admissions unnecessarily.

"The Government has to act before the care system collapses entirely."

A Department of Health spokesman said: "Just last week, the NHS was rated the number one health service in the world. Life expectancy continues to increase, with cancer survival rates at a record high whilst smoking rates are at an all-time low.

"We continue to invest to ensure our ageing population is well cared for, with £6bn extra going into the NHS over the last two years and an additional "£2bn for the social care system."