Number of Britons leaving the UK higher than previously thought

The number of British nationals who left the UK last year has risen from 77,000 to 257,000, according to revised immigration statistics. 

The Office for National Statistics (ONS) has changed its methods for calculating immigration by using people's interaction with public authorities as opposed to surveys.

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Estimates for net migration of British nationals were previously based on the International Passenger Survey, but the ONS said this had a very small sample size and had been "stretched beyond its original purpose".

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

It means that rather than the 77,000 British nationals who were thought to have left the UK in the year ending December 2024, 257,000 in fact left.

The statistics, published this morning, show there was also an increase in British nationals returning to the UK last year - up by 83,000 to 143,000, from 60,000.

The UK population is now also thought to be 97,000 lower than previously estimated.

The ONS tracks legal migration and some irregular migration.

It said migration from outside the EU had been the main driver of international immigration in recent years, largely due to work and study purposes, as well as for humanitarian reasons such as the Ukraine war.

The new data also shows that the peak of net migration - the number of arrivals minus the number of departures - was higher than previously thought.

The ONS estimates that net migration hit 944,000 in the year ending March 2023, which is higher than the previously estimated peak of 906,000 in 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 figures come amid a wide debate about immigration and asylum that saw the home secretary unveil the biggest policy changes to the UK since the Second World War.

Shabana Mahmood, the home secretary, told Sky News' political editor Beth Rigby that the number of illegal immigrants in the UK was "too high" and that she was "horrified" by the 27% increase in irregular arrivals in the year to June.

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On Monday, she unveiled a series of reforms to clamp down on the so-called "pull factors" bringing people to the UK, including what she called the "excessive generosity" of the asylum system.

Under the new plans, families with children will be removed - either voluntarily through cash incentives of up to £3,000, or by force.

The time successful asylum seekers must wait to claim permanent residency in the UK will also increase from five years to 20, and there will no longer be a legal obligation to provide financial support to asylum seekers - so those with the right to work but choose not to will receive no support.

In addition, a new appeals body will be set up to significantly speed up the time it takes to decide whether to refuse an asylum application.

Visas for countries refusing to accept deportees will also be banned and new safe and legal routes will be established.

(c) Sky News 2025: Number of Britons leaving the UK higher than previously thought