Males and females in Scotland and Wales, as well as males in Northern Ireland, saw a 0.1 year decline in life expectancy at birth. Life expectancy in England has remained unchanged from 2014 to 2016.
Northern Ireland also reported a decline of 0.1 year -- more than one month -- in the life expectancy of 65-year-old males for the past three years.
"2015 to 2017 saw the lowest improvements in life expectancy since the start of our series in 1980 to 1982," said Sophie Sanders, ONS statistician for the Centre of Ageing and Demography.
The report suggests annual fluctuations, like the seasonal flu, are possible reasons for the number of deaths.
The largest percentage increase in deaths in England and Wales, since 1968, was recorded in 2015. In 2017 deaths across England and Wales rose by further 0.7% from 2015, which could be another factor in the decline.
Life expectancy improvements have been slowing down in the UK since 2011.
"This slowing in improvements is reflected in the chances of surviving to age 90 years from birth, which has seen virtually no improvement since 2012 to 2014," added Sanders.
UK-wide, roughly one in five newborn males -- 21% -- and one in three females -- 32% -- could expect to live to their 90th birthday, with this largely unchanged since 2012.
When looking at life expectancy at the age of 65, the new data found that during 2015 and 2017, a 65-year-old male in the UK could expect to live another 18.6 years and a woman of the same age could expect an average of 20.9 further years.
'Something seriously wrong'
"I wasn't surprised by these findings," said Martin McKee, professor of European public health at the London School of Hygiene and Tropical Medicine. "We've been publishing for several years reports, warning that life expectancy has been stagnating since 2015."
McKee stated that the UK's population should "definitely" be worried about the new data.
"Because we know that whenever life expectancy slows down or goes into reverse that this is often a sign that there is something seriously wrong. It is always a very worrying development and often one of the first signs of political problems," he said."The problem of increasing deaths is mainly in older people and we are concerned that this has coincided with severe cuts to social care."
Globally several countries have reported a slowdown in life expectancy at birth and at age of 65 for both men and women, but the UK has reported one of the "largest" and remains lower than comparable countries, according to the ONS.
by the ONS shows that European countries, North America and Australia are also seeing no improvement, or declines, in life expectancy figures. A recent study
found a similar decline among affluent nations for the first time in decades.
Japan on the other hand continues to have one of the highest life expectancies. In Japan females can be expected to live to 87.0 years, four years longer than what the UK states as its life expectancy -- 82.9 years -- according to the ONS. Other European countries like Spain, Switzerland, France and Italy also have a female life expectancy over 85 years.
The greatest improvement in life expectancy at birth was recorded in the UK between 2009 and 2011, with an increase of 21 weeks for men and 18 weeks for women. The following years saw a decline and the new data published today shows life expectancy improvements of almost zero.
"The tailing off of increases in life-expectancy, and falls in some nations, could reflect the greater financial stresses experienced by this age group," said Amanda Burls, professor of public health at City University in the UK, adding that poverty is the most important socioeconomic determinant of health. "The distribution of the changes in life expectancy across the four nations of the United Kingdom provides some support to this hypothesis as England, where the greatest wealth lies, has been least affected. In addition the mortality rates in children have continued to fall."