Net migration to the UK: What numbers have changed and why?

Updated estimates of net migration to the UK have been published by the Office for National Statistics (ONS), based on improved methods for calculating the movement in and out of the country of British and EU nationals.

The revised figures suggest overall net migration in recent years peaked slightly higher and earlier than previously reported, and has since fallen more sharply.

Here the PA news agency explains which numbers have changed and why the revisions have taken place.

– Changes to overall net migration

Net migration to the UK is now estimated to have peaked at a record 944,000 in the year ending March 2023, up from an original estimate for this period of 894,000.

The peak was previously estimated to have occurred in the year to June 2023 at 906,000, but while this figure has also been revised upwards (to 924,000), it is no longer the highest on record and has been superseded by the new figure for the year to March 2023.

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

For example, in the peak year ending March 2023, 1.47 million people are now estimated to have immigrated long-term to the UK while 525,000 emigrated, producing the updated net figure of 944,000.

Since this peak, net migration has fallen more steeply than first reported.

The latest figure, for the year to December 2024, is now estimated to be 345,000, down 59% year on year from 848,000 in the previous 12 months.

Initial estimates for the year to December 2024 put net migration at a higher level of 431,000, down just under 50% year on year from 860,000.

These figures show that while the overall trends in recent years are similar to those previously published, net migration is now understood to have climbed even higher than initially estimated, since when it has fallen more sharply.

– Why have the estimates of net migration changed?

The changes reflect improvements made by the ONS in the way it estimates the migration patterns of two groups: British nationals and EU+ nationals (which covers the 27 countries of the European Union plus Iceland, Liechtenstein, Norway and Switzerland).

These patterns were always there – they have not suddenly been discovered – but they are now being more fully understood and more accurately measured.

The ONS has also made routine revisions to its estimates of the migration of non-EU+ nationals.

The change that has had the biggest impact on the overall estimates of net migration is the improvement in the calculation of the number of British nationals entering and leaving the country, with far more of this group believed to have left the UK than previously thought.

– Migration of British nationals

Estimates for net migration of British nationals were previously based on the International Passenger Survey (IPS), but this had become “stretched beyond its original purpose” of measuring travel and tourism and was based on a very small sample size, the ONS said.

Data collected as part of the 2021 census also suggested the survey was underestimating the level of migration of British nationals.

For its new estimates, the ONS has for the first time used data from the Department for Work & Pensions – specifically its Registration and Population Interaction Database, which covers everyone in the UK with a national insurance number.

This has been used to estimate the likely residency status of UK individuals and whether they have recently immigrated or emigrated.

The ONS still cannot monitor the actual travel patterns of UK migrants, as it can do with other nationality groups whose movements can be measured using Home Office borders and immigration data.

But the new method “has clear benefits over the previous survey-based approach” and has “very good coverage of British nationals”, the ONS added.

Using the new method, immigration and emigration of British nationals is “consistently higher” than previously estimated, in particular the number who are leaving the country.

Some 257,000 Britons are now thought to have emigrated from the UK in the year ending December 2024, up sharply from an initial estimate of 77,000.

At the same time, 143,000 British nationals are estimated to have immigrated to the UK in this period, up from 60,000.

Net migration of British nationals has been running at a negative level for many years – in other words, more of this group leave than arrive – but the figure is now greater than thought, standing at minus 114,000 in 2024, compared with an initial estimate of minus 17,000.

This larger negative figure has in turn helped bring down the overall estimate for net migration to the UK.

– Migration of EU+ nationals

The ONS has also improved the way it estimates the movement of EU+ nationals.

These figures are now based on Home Office borders and immigration data, which are “a more direct measure of migration flows”, the ONS said.

EU+ nationals require permission to migrate to the UK, typically in the form of a visa or by acquiring leave to remain, and this information is better captured by the Home Office than by using national insurance data from the Department for Work & Pensions, which was the previous method for this group.

The new estimates show net migration of EU+ nationals is still negative, with more people leaving than arriving, as has been the case since 2022.

The latest figure is slightly less negative than previously thought, however.

In the year to December 2024, an estimated 82,000 EU+ nationals immigrated to the UK while 150,000 emigrated, producing a net migration figure of minus 69,000.

The initial estimate for this period was minus 96,000.

– Migration of non-EU+ nationals

There has been no change in the way the ONS calculates its estimates for migration of people from outside the EU+ area, which continues to be based on Home Office borders and immigration data.

But there has been a routine revision of the latest figures, which is common between the publication of a first and second estimate and is due to more Home Office data becoming available.

Net migration for the non-EU+ group in the year to December 2024 is now estimated to be 528,000 (the difference between 790,000 immigrating long-term to the UK and 261,000 emigrating), down very slightly from an initial estimate of 544,000.

– The bigger picture

The cumulative impact of these changes and revisions is that net migration to the UK across the four years from 2021 to 2024 inclusive is now estimated to be 2.55 million, down from a previous estimate for this period of 2.65 million.

Annual net migration peaked higher and earlier than initially thought, but has since fallen more sharply.

The net migration estimate of 345,000 for the year to December 2024 is the lowest for any 12-month period since 251,000 in the year to June 2021.

The ONS will publish its first estimate for net migration in the 12 months to June 2025 on November 27.