Net migration fell more sharply than initially estimated, figures show

Net migration to the UK in recent years peaked at a higher level than initially estimated and has since fallen more sharply, new figures show.

Improved methods by the Office for National Statistics (ONS) suggest net migration hit a higher and slightly earlier peak of 944,000 in the year ending March 2023, compared with the previous estimate of 906,000 for the year ending June 2023.

This was followed by a sharper fall than initially reported, with net migration in the year ending December 2024 now estimated to be 345,000, lower than the original estimate of 431,000 that was published by the ONS in May of this year.

The main driver of the change in the net migration figures is an improvement to the way the ONS calculates the migration of British nationals.

Net migration is the difference between the number of people moving long-term to the UK and the number leaving the country.

Estimates for net migration of British nationals were previously based on the International Passenger Survey (IPS), but this had a very small sample size and had been “stretched beyond its original purpose”, so is no longer considered to be a reliable measure, the ONS said.

The estimates are now produced using more robust and comprehensive data from the Department for Work & Pensions, which incorporates everyone with a national insurance number and which can be used to determine the likely migration status of UK individuals.

The improved figures mean estimates of the emigration by British nationals being revised upwards.

In 2024, some 257,000 British nationals are now estimated to have left the UK, compared with an initial estimate of 77,000.

Improvements have also been made in the way the ONS estimates the movement of EU+ nationals, which covers the 27 countries of the European Union plus Iceland, Liechtenstein, Norway, and Switzerland.

Mary Gregory, director of population statistics at the ONS, said the independent statistics body has been exploring different data sources to overhaul its estimates, after the Census 2021 showed the International Passenger Survey was underestimating the number of British people abroad.

“Understanding the long-term international migration patterns of British nationals has been, and always will be, challenging due to the sheer number of British people crossing the border on a daily basis,” she said.

“Very few of these will be migrants and British people don’t need a visa to travel to the UK so we cannot use HOBI data to estimate migration of British nationals.

“Based on these new data and methods, it is clear the IPS continued to underestimate British emigration since 2021, and it also underestimated immigration.”

Research affiliate Georgina Sturge, of Oxford University’s Migration Observatory, said the new method “almost certainly” gives a more accurate picture of migration but “uncertainties remain”.

“The method for estimating migration of British citizens is very much experimental and future revisions are likely,” she said.

“But it is reassuring that the British emigration figure is now more plausible than previous estimates.

“Another uncertainty is that there is still no good method for taking into account EU and non-EU visa overstayers.”

The revised figures and method update have been published ahead of the latest long-term international migration statistics in the year to June 2025, which will be released on November 27.