A new CPS briefing outlines the scale of this demographic change, and explores the idea of an emergency census in 2026
New analysis by the Centre for Policy Studies of revised ONS population data, released this week, highlights the extent to which earlier population figures understated recent demographic change in the United Kingdom.
The revised long term international migration data published by the ONS shows that the country experienced faster population growth and greater churn between 2021 and 2024 than was previously recognised – on a scale that it is hard to find a historical equivalent for.
The updated estimates indicate that around one in 25 people currently living in the United Kingdom arrived during this period, and that the foreign-born population is now close to 20%. These changes were not fully captured in earlier statistics, which relied on outdated data sources.
One of the clearest examples concerns emigration: the previous ONS series had suggested that around 332,000 British nationals left the country between 2021 and 2024, whereas the revised data puts the true figure at 992,000, around 190 per cent higher than thought, and an average of 679 people leaving each day.
‘A Migration Revolution’ by CPS Research Director of Research Karl Williams shows how earlier estimates understated overall population growth, inflows, and the size of the foreign-born population.
It highlights that despite the ONS’s efforts to improve its figures, there are still huge uncertainties around the scale and composition of recent migration. Williams argues that the latest news strengthens the case for the idea of an emergency census in 2026, which some commentators have proposed, in order to provide an authoritative assessment of the United Kingdom’s population after a period of unusually rapid demographic change.
Centre for Policy Studies Director of Research, Karl Williams, said:
‘This new data shows just how significant recent population change has been. The combined effect of record inflows and the sharp rise in emigration has reshaped the country far more quickly than most people realise.
‘If decisions on housing, public services and local funding are to keep pace with these shifts, we need a precise and up-to-date picture of the population.’
Read more on The Centre for Policy Studies

