The impact of Brexit on immigration to the UK

Jonathan Portes and John Springford share their new analysis that estimates how the number of foreign-born workers would have evolved had the UK remained in the EU. They argue that while leaving changed the composition of migration flows dramatically, it did not materially alter the underlying balance between labour demand, demographic pressures and political constraints.

When the UK voted to leave the EU, much of the economic debate focused on two channels: trade and migration. While there has been extensive work on Brexit’s effects on trade and GDP, its impact on immigration – particularly on the size and composition of the workforce – has been less systematically examined.

In a new analysis, we estimate how the number of foreign-born workers in the UK would have evolved had the country remained in the EU. The results suggest that ending free movement and introducing a new immigration system in 2021 led to a modest rise in the number of foreign born workers in the UK, but a dramatic shift in their countries of origin.

Before and immediately after the 2016 referendum, most forecasts suggested that Brexit would reduce overall immigration. The end of free movement was expected to cut EU inflows, only partially offset by a more liberal regime for non-EU workers. The Home Office, for example, estimated that the post-Brexit system would reduce work-related migration by around 40,000 per year.

What happened instead was more complex. Following the introduction of the new system in January 2021, net migration rose sharply, reaching record levels in 2023. That surge prompted successive Home Secretaries to tighten visa rules. Combined with a weakening labour market, this has led to a sharp fall in work visas issued, including dependants – from 541,100 in 2023 to 186,000 in 2025, with further declines in recent months.

The political debate has often treated these developments as clear evidence either of regained “control” or of policy failure. Our findings point to a more nuanced picture.

It is not possible simply to attribute post-2016 changes in migration to Brexit. The pandemic, post-pandemic labour shortages, the war in Ukraine and the visa route for Hong Kong British Nationals (Overseas) all influenced flows. To isolate the effect of Brexit, we apply a synthetic difference-in-differences approach. In essence, we construct a “counterfactual UK” using a weighted average of comparable EU-15 and EEA countries that closely matched UK trends in foreign-born employment before the referendum. This method improves on simply assuming existing trends continue, and avoids relying on a single comparator country such as Germany.

We focus on foreign-born employees rather than immigration flows. UK flow data have been repeatedly revised, and the Labour Force Survey has had well-documented sampling issues for migrants. Instead, we use HMRC data on non-national employees for the UK and Eurostat data on foreign-born employees for comparator countries. Concentrating on workers also reduces the influence of country-specific shocks to asylum and refugee numbers, which might distort the results.

We estimate effects separately for EU-origin and non-EU-origin workers. For EU workers, we treat the referendum in June 2016 as the start of the “treatment”, reflecting the immediate political and economic uncertainty, including sterling’s depreciation. For non-EU workers, we treat January 2021 – when the new system came into force – as the relevant break point. However, using either 2016 or 2021 for both does not hugely change results

For EU-origin workers, the divergence between the UK and its counterfactual is substantial. By 2024, the number of EU-origin workers in the UK had returned roughly to its 2016 level. In our counterfactual UK, it had risen by around 30 per cent. That implies that Brexit reduced the number of EU-origin employees by about 785,000 by 2024 – equivalent to roughly 2.6 per cent of the total UK workforce. Most of this effect had materialised by 2023, with both the actual and counterfactual series flattening thereafter.

This confirms that ending free movement had a substantial and lasting effect on EU labour supply to the UK.

The story for non-EU workers runs in the opposite direction. After 2021, non-EU employment rose sharply in the UK – far more than in the counterfactual. By the end of 2024, non-EU employment in the UK had reached about 225 per cent of its 2016 level, compared with about 150 per cent in the synthetic control. We estimate that Brexit increased the number of non-EU employees by around 992,000 in 2024. Unlike the EU effect, this divergence continued to grow through 2024, consistent with a sustained increase in work-related migration under the new system.

However, more recent data, not included in our analysis, suggests that this expansion appears to have peaked. Visa data indicate that work-related non-EU migration slowed sharply in 2025 as the government tightened rules and labour shortages eased. The additional boost to non-EU employment seen in 2024 is therefore unlikely to persist at the same pace.

Combining these two large but offsetting shifts, we estimate that the net effect of Brexit in 2024 was an increase of around 207,000 non-UK-origin employees – approximately 0.6 per cent of the total workforce. In other words, Brexit substantially reduced EU-origin employment and substantially increased non-EU-origin employment. But the overall number of foreign-born workers in the UK was only modestly, although significantly, higher than it would have been had the UK remained in the EU.

The broader political economy challenge remains. Across Europe, ageing populations are increasing demand for migrant labour, even as public and political pressures push governments to reduce immigration. The UK is not unique in facing this tension.

Our analysis suggests that leaving the EU did not resolve that dilemma. It changed the composition of migration flows dramatically, and it restored nominal “control” over the nature of those flows, but it did not materially alter the underlying balance between labour demand, demographic pressures and political constraints.

By Professor Jonathan Portes, Senior Fellow, UK in a Changing Europe and John Springford, Associate Fellow, Centre for European Reform.