Forecasting future migration levels is extremely difficult because the drivers of migration are so complex. ONS produces population projections for the UK and local authorities based on a number of assumptions, such as the fertility rate, life expectancy and the level of migration. These figures therefore provide some indication of future changes in the size of the immigrant population in relation to the rest of the UK population. Population projections come with significant uncertainty as a result of changing demographic and economic trends as well as changes to government policy, including migration policy. Users should bear in mind that the UK’s actual future immigrant and total populations are bound to differ from these projections.
Population projections are provided separately for England, Wales, Scotland and Northern Ireland and generally cover a period of 25 years.
- England: ONS provides data for download on the expected annual contribution of migration to future populations across local authorities in England for 25 years.
- Scotland: NRS provides similar data to the ONS for local authorities in Scotland.
- Wales: The Welsh Government provides local-level population projections for Wales.
- Northern Ireland: Population projections for Northern Ireland are published by NISRA. The contribution of migration to population growth in local areas is accessible on their website through an interactive dashboard or by downloading the data.
Figure 10 shows the total projected population change in English local authorities between 2016 and 2041. It also shows ‘natural change’ – i.e., the expected population change due to the number of births minus the number of deaths – and population change due to net international migration and net internal (within-UK) migration.