New official statistics reveal a dramatically revised picture of migration to the United Kingdom, showing that net migration reached a higher peak and has since fallen more steeply than previously thought.
A Revised Migration Timeline
The Office for National Statistics (ONS), using improved calculation methods, now estimates that net migration peaked at 944,000 in the year ending March 2023. This figure is not only higher but also occurred slightly earlier than the prior estimate of 906,000 for the year to June 2023.
The subsequent decline was also more pronounced. For the year ending December 2024, net migration is now placed at 345,000. This is a significant downward revision from the original estimate of 431,000 published by the ONS in May of this year.
The Driver of Change: A New Method for Counting British Nationals
The primary reason for this substantial revision is a major overhaul in how the ONS calculates the migration of British citizens. The statistics body concluded that the long-relied-upon International Passenger Survey (IPS) had a sample size that was too small and had been stretched beyond its original purpose, making it an unreliable measure.
Instead, the new estimates are produced using more robust data from the Department for Work and Pensions, which incorporates everyone with a National Insurance number. This comprehensive dataset allows for a more accurate determination of the likely migration status of UK individuals.
This methodological shift means that estimates for the emigration of British nationals have been revised sharply upwards. For 2024, the ONS now estimates that 257,000 British nationals left the UK, a figure vastly higher than the initial estimate of just 77,000.
Expert Reaction and Remaining Uncertainties
Mary Gregory, the ONS Director of Population Statistics, explained the challenge, stating, “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 confirmed that the IPS had been underestimating both British emigration and immigration since 2021.
Georgina Sturge, a research affiliate at Oxford University’s Migration Observatory, commented that the new method “almost certainly” provides a more accurate snapshot of migration flows. She noted that the revised figure for British emigration is now “more plausible,” but cautioned that “uncertainties remain.”
“The method for estimating migration of British citizens is very much experimental and future revisions are likely,” Sturge said, also highlighting that there is still no reliable method for accounting for EU and non-EU visa overstayers.
These revised figures were published ahead of the next set of long-term international migration statistics for the year to June 2025, which are scheduled for release on November 27.
