Rejoining the European Union could increase net migration by more than 200,000, according to analysis by Reform UK.

Modelling by Nigel Farage’s party suggests that the restoration of free movement from the EU could push net migration over 500,000, more than 200,000 above the official estimates by the Office for Budget Responsibility (OBR).

Net migration, the number entering the UK minus those leaving, stood at 171,000 at the end of last year, down from a peak of 944,000 for the year ending December 2023.

Reform’s analysis claimed that increases in migration from the EU if the UK were to rejoin would more than compensate for a 60 per cent decline in the number of foreign workers from non-EU countries.

The modelling comes after Andy Burnham last week said he wanted to review all the options on the UK’s relationship with the EU, from maintaining the status quo to “going all the way” and rejoining the bloc.

However, Mr Farage, the Reform leader, said: “This is Brexit betrayal writ large. Burnham wants to open the borders to nearly half a billion people with no way of controlling who enters the country. It’s clear that Open Borders Burnham doesn’t care about the British public’s concerns about immigration.”

The Reform modelling recalculated net migration from 2021 to 2025 as if Brexit had not happened, assuming a higher influx of migrants from the EU and a lower number from non-EU countries. This meant net migration was 425,000 higher over the five years than post-Brexit reality.

The model suggested it stood at 375,000 for the year ending December 2025, some 204,000 higher than the current figure of 171,000.

Applying the model to the years 2026 to 2030, it predicted net migration would be about 175,000 higher as a result of rejoining the EU. “Rejoining in 2028, with EU flows recovering over three years, would leave net migration around 214,000 a year higher by 2030 than staying out,” it predicted.

Madeleine Sumption, director of Oxford University’s Migration Observatory, said that although she could not project any figures, it would be highly unexpected for there not to be an increase in migration if Britain rejoined the EU.

This was because the EU would move to a situation where its citizens would be free to come to the UK for any type of job rather than being restricted to graduate-level work or short-term visas, she said.

“It’s not unreasonable that numbers would go back to something broadly similar to what we saw pre-Brexit,” she added. Then, net migration was largely around 200,000 to 300,000 a year.

There was, however, a caveat that Poland, one of the main sources of EU migration into the UK pre-Brexit, was substantially richer, while Romania, another major source of migration, was also getting richer, she said.

Responding to the Reform analysis, a government spokesman said: “We do not recognise this analysis. Net migration is down by 82 per cent since it peaked under the last government following Brexit, while the number of people arriving by small boat is down 40 per cent compared to last year. However, there is still more to do.

“Immigration will be one of the key issues on the agenda when UK and EU leaders meet at a summit later this year.”

The Centre for Migration Control said: “It is important that the public are aware of the risks associated with a return of freedom of movement rules. This is why this modelling is so important, as it highlights the potential scale of what has been put on the table by this Labour government.

“There is no doubt that rejoining the EU would lead to a spike of migration from the continent, especially the likes of Romania and Bulgaria, reversing several years of European net negative migration.

“There is a danger that inward migration surges, especially in the absence of labour market reform, and the British government would simply be unable to do anything about it.”

Rejoining the EU ‘Could Increase Net Migration by 200,000’

Britain’s future relationship with the European Union has returned to the centre of political debate after Prime Minister Andy Burnham reopened the question of whether the United Kingdom should consider rejoining the bloc. The possibility has reignited disagreements over immigration, national sovereignty, economic growth and the consequences of Brexit, with Reform UK warning that reversing Britain’s departure could significantly increase net migration.

According to modelling published by Reform UK in October 2026, rejoining the European Union and restoring freedom of movement could increase annual net migration by approximately 214,000 by 2030 compared with a scenario in which Britain remained outside the bloc. The party argues that such a change would make it more difficult for the government to control immigration and respond to public concerns about population growth.

However, the figure is not an official government forecast or a confirmed prediction of what would happen if Britain rejoined the EU. It is an estimate based on assumptions about future migration patterns, including the number of European citizens who might move to Britain and possible changes in migration from countries outside Europe. <Cite refs={[“turn518505search0″,”turn518505search1”]}/>

The debate nevertheless raises important questions about Britain’s post-Brexit future. Supporters of closer European integration argue that renewed membership could improve economic opportunities, strengthen international cooperation and make it easier for British citizens to live and work across Europe. Critics counter that restoring freedom of movement could place additional pressure on housing, infrastructure and public services.

For Burnham’s government, the challenge is to examine these competing arguments while explaining clearly what any future change in Britain’s relationship with Europe would mean for the public.

Why the Migration Figure Has Become a Political Flashpoint

Reform UK’s analysis examined what migration might have looked like between 2021 and 2025 if Britain had not left the European Union. Its model assumed that immigration from EU countries would have been higher, while migration from outside Europe would have been lower under the alternative scenario.

According to the party, the difference between the two scenarios would have amounted to approximately 425,000 additional net migrants over five years. For the year ending December 2025, Reform’s model estimated that net migration could have reached approximately 375,000 rather than the recorded figure of 171,000.

The party then used these calculations to estimate that restoring freedom of movement following a hypothetical return to EU membership in 2028 could increase annual net migration by approximately 214,000 by 2030. <Cite refs={[“turn518505search0”]}/>

These figures are politically significant because immigration has remained one of the most contested issues in British public life since the Brexit referendum in 2016.

For Reform UK, the projections support its argument that leaving the EU gave Britain greater control over immigration policy. The party contends that rejoining would reverse an important consequence of Brexit and make it harder for the government to determine how many European citizens could move to the country.

Nevertheless, the assumptions behind the modelling matter. Migration depends on employment opportunities, wages, housing availability, economic conditions, family circumstances and government policy. The number of people who arrive in Britain is also different from the number who remain in the country over the longer term.

Consequently, a model describing one possible scenario should not be confused with a definitive forecast of future migration.

What Does Net Migration Actually Mean?

Understanding the debate requires distinguishing between immigration and net migration.

Immigration measures the number of people moving into a country, while net migration represents the difference between long-term immigration and long-term emigration over a specified period.

If 500,000 people move to Britain and 350,000 leave, net migration would be 150,000. The net figure therefore reflects both arrivals and departures rather than simply counting everyone who enters the country.

The distinction is important because the restoration of freedom of movement would not necessarily mean that every additional arrival would remain in Britain permanently. Some European citizens might come to work or study for a limited period before returning home, while British citizens could also take advantage of greater opportunities to live and work in EU member states.

The Migration Advisory Committee has emphasised that migration statistics need to be interpreted carefully and that the economic and fiscal effects of migration depend on factors including migrants’ employment, earnings, length of stay and use of public services. <Cite refs={[“turn518505search2”]}/>

An increase in net migration could contribute to a larger workforce and greater economic activity. At the same time, population growth can increase demand for housing, transport, healthcare and education if investment does not keep pace.

The overall effect therefore depends on the circumstances surrounding migration and the government’s ability to plan for population changes.

Andy Burnham Reopens the Brexit Debate

The controversy follows Burnham’s September 2026 comments that Britain should examine all available options for its long-term relationship with the European Union, including the possibility of rejoining.

Speaking during Labour’s annual conference, Burnham argued that Brexit had caused significant economic difficulties and that Britain should reconsider whether its current arrangements with Europe were delivering the benefits promised by supporters of leaving.

He did not announce an immediate plan to rejoin the EU or commit the government to holding a new referendum. Instead, he called for a review of Britain’s future relationship with its European partners. <Cite refs={[“turn518505news9”]}/>

The distinction matters because closer cooperation with the EU does not necessarily require full membership.

Britain could explore improvements to existing trade arrangements, pursue a customs agreement, seek closer access to the single market or consider a more comprehensive relationship. Each option would involve different economic benefits, political obligations and implications for immigration.

Full EU membership would raise particularly important questions about freedom of movement, financial contributions to the EU budget and the application of European rules.

Burnham’s decision to keep the options open has therefore created a debate about the balance between economic opportunity and political control.

Supporters of reconsidering Brexit argue that Britain should be willing to evaluate the available evidence rather than treating the 2016 referendum as the end of the discussion. Critics respond that a fundamental change in the country’s relationship with Europe would require a clear democratic mandate and a transparent explanation of the consequences.

Could Rejoining the EU Benefit Britain’s Economy?

The debate is not exclusively about immigration. Supporters of rejoining argue that closer integration could improve trade, investment and economic growth.

British businesses operating across European markets face administrative requirements and regulatory barriers that did not apply in the same way when the UK was an EU member. Rejoining could potentially reduce some of these obstacles and make it easier for companies to trade, recruit workers and coordinate investment across borders.

A report discussed by Goldman Sachs in October 2026 estimated that closer economic integration could increase Britain’s long-term economic output, with the potential effect varying according to the arrangement chosen. The analysis suggested that full EU membership could produce a larger economic benefit than maintaining the existing relationship. However, such estimates depend on assumptions about trade, investment and the wider economic environment. <Cite refs={[“turn518505news6”]}/>

Supporters also argue that membership could strengthen Britain’s influence in European decision-making and improve cooperation on issues including energy security, research and international security.

However, economic benefits would not automatically be distributed equally across the country. Some industries could benefit more than others, while businesses would still face competition and the costs associated with adapting to changes in regulation.

Nor would stronger trade relationships resolve every domestic economic problem. Productivity, housing supply, skills, infrastructure and investment would remain important determinants of living standards.

The economic case for rejoining must therefore be considered alongside the costs, obligations and political trade-offs involved.

Immigration, Housing and Pressure on Public Services

One of the most sensitive aspects of the debate concerns the capacity of public services to respond to population growth.

In areas where housing construction has failed to keep pace with demand, additional population growth can intensify competition for available homes. Local authorities may also face increased demand for school places, transport and healthcare.

However, the relationship between migration and public-service pressure is not determined by population numbers alone. Funding, infrastructure investment, workforce planning and the geographical distribution of population growth all matter.

Migrants also contribute to the economy through employment, taxation and the provision of services. In some sectors, including healthcare and social care, international recruitment has helped employers fill vacancies that would otherwise be difficult to staff.

The Migration Advisory Committee’s research stresses that the fiscal effects of migration vary according to migrants’ characteristics and circumstances