Deaths have outnumbered births annually in the UK for the first time in nearly 50 years, excluding the Covid pandemic, new official figures show.
There were 16,300 more deaths than births in the year to June 2023, the Office for National Statistics (ONS) said. In Scotland and Wales, deaths outnumbered births while the opposite occurred in England and Northern Ireland, although not by a large margin.
The UK population still increased by the largest amount since the early 1970s, with net migration the main contributor across all four countries.
The ONS says the population grew by 662,400 to an estimated 68,265,200 people in the year to mid-2023 - a 1% increase.
Net international migration, the difference between the number of people arriving in the UK and leaving, is estimated at 677,300 for the year to mid-2023.
Figures show that, without that net migration figure, the UK's population would have fallen.
Downing Street said Sir Keir Starmer had been "clear that overall net migration does need to come down" and the government would "end the situation where legal migration is used as an alternative to tackling skill shortages in the UK".
Scotland had 19,000 more deaths than births in the year to June 2023, and Wales recorded 9,500 more.
In contrast, there were 9,800 more births than deaths in England, and 2,500 more in Northern Ireland .
These figures mean the UK had a negative natural change in the population for the first time since 1976, with the exception of the Covid pandemic year of 2020. The ONS added the figures in 1976 were based on year-end data, rather than mid-year data.
The overall UK population is estimated to have risen by 1% in the year to June 2023, which the ONS says is the largest annual percentage increase since 1971 when the current series of mid-year estimates began.
It follows a rise of 0.9% in the year to mid-2022.
All population estimates are likely to be revised within the next year as new data becomes available and improvements to estimates of international migration continue to be made, the ONS added.
One expert told the PA news agency the negative natural change is "not unexpected" due to the low rate of babies being born and the large post-war birth cohorts now entering old age having had longer lives.
"The number of deaths we expect will increase each year over time as this generation of older adults ages and dies," Professor Sarah Harper, director of the Oxford Institute of Population Ageing, added.
Separate figures released in May showed UK net migration for the year to December 2023 was estimated to be 685,000 - down from 764,000 for the 12 months to December 2022, but more than three times higher than in 2019.
The Migration Observatory at the University of Oxford said in May net migration "remained at unusually high levels".
Reacting to today's figures, the prime minister's spokesman said rules around migrant sponsorship would be toughened "to ensure employers guilty of flouting employment laws are banned from hiring from abroad".
Prior to the general election, the previous Conservative government said the drop in net migration showed its plan to bring down the figure was working.
The latest figures suggest the population grew faster in the year to mid-2023 in England and in Wales (both 1%) than in Scotland (0.8%) or Northern Ireland (0.5%).
This was the highest rate of annual growth for England, Wales and Scotland since comparable data began in 1971, while for Northern Ireland it was the highest since mid-2019.
An ONS projection released in January suggested the UK population could reach nearly 74 million by 2036 with net migration fuelling that rise.
Figures from the ONS projected a net migration of 6.1 million people and about 500,000 more births than deaths, as well as an additional one million people aged 85 and over in the UK by 2036.
