Debate on impact of the 2016 EU membership referendum on the UK

Following the 2016 UK referendum vote in favour of leaving the EU, on 29 March 2017 the UK Government triggered the EU’s “Article 50” procedure to commence negotiations on withdrawing from the EU. After an earlier version of the Withdrawal Agreement negotiated by Theresa May’s government did not win the support of the House of Commons, a revised version of the Withdrawal Agreement was finalised by Boris Johnson’s government and the EU in October 2019. Legislation to implement the agreement was approved by Parliament in January 2020 and the UK left the EU on 31 January 2020.

The Withdrawal Agreement included provisions for a Brexit transition period until the end of 2020, during which EU rules continued to apply to the UK and the UK remained part of the EU single market and customs union. During this period, the UK and the EU negotiated a new agreement to govern their future relationship.

EU treaties ceased to apply to the UK at the end of the Brexit transition period on 31 December 2020, with the UK leaving the EU single market and customs union.

The “future relationship agreement”, the UK–EU Trade and Cooperation Agreement, was finalised in late December 2020 and came into force provisionally on 1 January 2021. The agreement was fully implemented on 1 May 2021, following ratification by both the UK and the EU.

For a timeline of events leading up to the 2016 referendum, withdrawal from the EU on 31 January 2020 and the Brexit transition period until 31 December 2020, see the Commons Library briefing Brexit timeline: events leading to the UK’s exit from the European Union

Principal UK–EU treaties following UK withdrawal from the EU

The Withdrawal Agreement and the Trade and Cooperation Agreement are the two principal treaties that have governed the UK–EU relationship since the UK’s withdrawal from the EU and the end of the Brexit transition period.

Withdrawal Agreement

The UK–EU Withdrawal Agreement came into force when the UK left the EU on 31 January 2020, although parts of it were not fully implemented until the end of the Brexit transition period. The Withdrawal Agreement covered issues related to the legal separation of the UK from the EU, including the settlement of UK financial obligations to the EU and the status of UK and EU citizens living in each other’s territory at the end of the transition period. It also included the protocol on Northern Ireland/Ireland which has subsequently been amended and is now referred to as the Windsor Framework.

Further information

For further details of the Withdrawal Agreement, see the Commons Library briefing The UK's EU Withdrawal Agreement, July 2019. The briefing provides a detailed overview of the earlier version of the Withdrawal Agreement agreed by Theresa May’s government and the EU in November 2018. Although the provisions of the Northern Ireland Protocol were substantially revised, the other provisions of the agreement remained unchanged in the final version agreed in October 2019.

For details of the changes to the Northern Ireland Protocol in the final version of the agreement, see the Commons Library briefing The October 2019 EU UK Withdrawal Agreement (October 2019).

For an overview of the Northern Ireland Protocol and the changes under the Windsor Framework, see the Commons Library briefing The Northern Ireland Protocol and Windsor Framework.

Trade and Cooperation Agreement

The UK–EU Trade and Cooperation Agreement (TCA) was finalised in late December 2020 and then came into force on 1 January 2021. The TCA covers UK–EU trading arrangements, including tariff-free trading provisions for goods that meet specific rules of origin and “level playing field” provisions to address different regulations in some policy areas that might distort trade and “fair competition”. The agreement also includes new arrangements on access to fishing waters and cooperation in other areas, including law enforcement and UK participation in EU programmes.

Further information

For further details on the TCA, see the Commons Library briefing The UK-EU Trade and Cooperation Agreement: summary and implementation (December 2020).

For an overview of the governance provisions in the TCA, see the Commons Library briefing The UK-EU Trade and Cooperation Agreement: governance and dispute settlement (August 2021).

For a summary of the TCA provisions and comparison with those in the Withdrawal Agreement, see the Commons Library briefing Governing the new UK-EU relationship and resolving disputes (February 2021).

Commons Library briefings covering various aspects of the post-Brexit UK–EU relationship can be found on the Commons Library collection page UK-EU relationship after Brexit.

End of free movement and control of EU migration

Following the end of the Brexit transition period, EU free movement rules ceased to apply to the UK. This had been a stated aim of many supporters of the UK leaving the EU, and of the UK Government in implementing the 2016 referendum result. This related to the then government’s objective of exercising control over EU migration to the UK and reducing the numbers of EU citizens coming to live in the UK (see below).

Since the end of the Brexit transition period, UK citizens have been categorised as “third country nationals” by the EU for the purpose of travel to the EU/Schengen area, although the UK has been added to the list of countries whose citizens do not need a visa for short stays to the EU/Schengen area. As with other third-country nationals, under these rules UK citizens can only stay in the EU/Schengen area for a total of 90 days in a rolling 180-day period. Stays beyond this limit (including for work and study purposes) would normally require a visa or residence permit and be subject to the immigration rules of individual member states.

The status of UK citizens who were already resident in EU member states at the end of the Brexit transition period differed in that they were able to continue their residence status in the host member state under the Withdrawal Agreement. However, UK citizens with this status in EU member states do not have the right to free movement across the EU.

Further information

For further information on the rules for visiting, living and working in the EU/Schengen area, see the Commons Library briefing After Brexit: Visiting, working, and living in the EU.

The EU has implemented a new automated border system, the EU entry/exit system (EES) which is being used to ensure compliance with the 90/180-day rule. The EU also intends to implement an electronic travel authorisation system that will apply to UK citizens. For further information on these systems, see the Commons Library briefing The EU Entry/Exit system and EU travel authorisation system.

Migration trends since Brexit

As noted above, an objective of campaigners who wanted to leave the EU was for the UK to exercise control over EU migration to the UK and to reduce the number of EU citizens coming to live in the UK.

The chart below identifies changes in migration levels in the period leading up to the decision to leave the EU in 2016, and the period since then. It shows estimated net migration to the UK by EU+ and non-EU+ nationals from 2012 to 2025. The EU+ grouping includes all current EU countries plus Norway, Iceland, Liechtenstein and Switzerland. Non-EU+ includes all other foreign nationals.

Net migration is the difference between the number of people immigrating and the number emigrating in a specified period. This indicates how much migration is adding to or taking away from the population.

In the years before the EU referendum in June 2016, net migration of EU+ nationals consistently exceeded that of non-EU+ nationals, reaching an estimated 322,000 in the year to June 2016. This was around four times higher than the equivalent figure of 82,000 for non-EU+ nationals.

In the period since the referendum, there has been a notable shift in migration patterns. Following the referendum, net migration by EU+ nationals began to fall and has since declined fairly steadily. Net migration estimates have been negative since the year ending June 2022, indicating that more EU+ nationals are leaving the UK than arriving.

The reduction in net migration from EU+ countries was accompanied, and more than offset, by a substantial increase in net migration from non-EU+ countries. From 2012 to 2019, net migration of non-EU+ nationals increased fairly modestly, before dipping slightly in 2020 at the start of the covid-19 pandemic. Net migration from non-EU+ countries then increased sharply in 2021 and 2022, peaking at 1.05 million in the year ending March 2023, before declining again in subsequent years.

The Migration Advisory Committee, an independent group that advises the government on migration, has identified three main factors behind the post-pandemic rise in net migration:

• an increase in work visas, particularly in health and social care
• an increase in student visas
• the opening of new humanitarian routes, such as the British National (Overseas) visa for Hong Kong residents and the Ukraine schemes

Note: The Office for National Statistics (ONS) is currently implementing a new methodology for estimating long-term migration. The estimates presented here are classed as ‘official statistics in development’ and may be subject to further revision as the methodology for producing them is refined.

Source: ONS, Long-term international migration, provisional: year ending December 2025, 21 May 2026, Table 1

Further information

Further analysis of the latest migration statistics can be found in the Commons Library briefing Migration statistics. The Migration Observatory at the University of Oxford has also published a briefing on Net migration to the UK.

Regulatory divergence

Some supporters of the UK leaving the EU saw it as way of giving the UK the freedom to diverge from EU regulatory standards. The UK in a Changing Europe thinktank publishes a UK-EU regulatory divergence tracker, outlining how UK and EU rules and regulations have diverged since Brexit. Its latest divergence tracker report was published in April 2026.

At the end of the Brexit transition period, under the provisions of the European Union (Withdrawal) Act 2018, EU law applying in the UK was converted into “retained EU law” as a type of UK domestic law. This was to provide legal continuity, with a view to decisions being taken later as to which laws to amend, replace or revoke. Further legislation was subsequently passed in 2023 to change the status of retained EU law (which has been called ‘assimilated law’ since 1 January 2024).

The UK Government has published information on how much assimilated law has been revoked or reformed. The most recent government report was published in January 2026 and updated in July 2026. It states that, as of 23 June 2026, out of a total of 6,925 assimilated laws:

• 4,221 were unchanged
• 929 had been amended
• 1,634 had been repealed
• 62 had been replaced
• 75 had expired.

Independent trade policy

Another aim of many supporters of the UK leaving the EU, and of the UK Government in implementing the 2016 referendum result, was for the UK to have an independent trade policy.

Since leaving the EU, the UK Government says it has signed 40 trade agreements with 74 countries and territories plus the EU. These agreements are in force for 73 partners. Most of these are “roll over” agreements, replacing agreements with countries that the UK was party to as a member of the EU.

However, there have been new agreements with countries not previously covered by EU agreements, including Australia, New Zealand and India.

The UK has also joined the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, a trade agreement involving 11 other countries in the Asia-Pacific region.

Further information

For further details on the new trade agreements signed or being negotiated by the UK, see the Commons Library briefing Progress on UK free trade agreement negotiations.

Economic impact of Brexit

The exact economic impact of Brexit is hard to quantify. However, many economists agree that Brexit likely reduced UK GDP compared with what it would have been otherwise, and that it had an adverse effect on UK trade.

GDP

A broad consensus among economists is that Brexit has resulted in the UK economy being smaller than it otherwise would have been.

The mainstream view is that Brexit has made trading with the EU more difficult, with additional customs checks and higher barriers to trade raising business costs, negatively affecting trade and investment (and therefore the UK economy as a whole).

Research on the impact of Brexit on GDP

Studies have estimated that UK GDP (a measure of total UK economic output) is 2% to 8% lower than if the UK had stayed in the EU. In other words, the economy has still grown since the 2016 referendum, but by less than it would have done otherwise.

Bloomberg Economics estimates that UK GDP is 2% to 4% lower than it would have been due to Brexit. It estimates that the long-term negative impact of Brexit is 2.5% of GDP, which it says leads to about £30 billion in annual foregone tax revenue.

Simon French, chief economist at the investment bank Panmure Liberum, estimates that UK GDP is 2.5% lower than if the UK had stayed in the EU, citing underperformance in trade, a persistent “uncertainty premium” on UK financial assets and weaker business investment. He also argues that the Brexit process consumed so much political attention that the more important domestic barriers to growth, such as high industrial electricity prices and housing supply, were neglected.

Goldman Sachs, the investment bank, estimates that UK GDP is around 6% below what it would have been if the UK was still in the EU, with lower trade and business investment the main ways in which Brexit has affected the economy.

Research by Nichols Bloom and colleagues, published by the US National Bureau of Economic Research, estimated that UK GDP per person was 6% to 8% lower than it would have been without Brexit. The economic effects include persistent uncertainty leading to weaker investment, higher trade costs, and management time being diverted from other activities to prepare for Brexit.

The Office for Budget Responsibility (OBR), the UK’s official independent economic forecaster, expects productivity and therefore GDP to be 4% lower in the long run compared with a scenario where the UK remained in the EU. The OBR derived this figure in March 2020 from a review of 13 studies published from 2016 to 2019, using the average of their estimated long-run productivity effects of Brexit. As of mid-2026, this assumption about the economic impact of Brexit is still used by the OBR.

Some economists think that several of these estimates overstate the negative economic impact of Brexit. Julian Jessop published a presentation on Brexit in August 2024 providing a critique of some of the analytical techniques used, including those used by the OBR. He has also written about what he considers flaws in some of the Brexit impact studies mentioned above.

Other commentators have similarly argued that research suggesting Brexit has had a relatively large effect on the UK’s GDP is overstated and based on unrealistic assumptions and economic modelling choices.

Difficulty in assessing the effects of Brexit of GDP

Assessing Brexit’s impact on the UK economy is complicated by a number of factors, including:

• the impossibility of knowing with certainty how the economy would have performed had the UK remained in the EU
• other major events and factors, such as the covid-19 pandemic and the conflict in Ukraine (including the attendant rise in energy prices), which have had big effects on the economy
• the increasing amount of time that has passed since the referendum and the UK’s subsequent departure from the EU, which makes it increasingly difficult to try and isolate the effects of Brexit from the myriad other economic developments that have affected the UK

Although the studies cited above attempt to account for these factors and isolate the effects of Brexit, this is difficult to do and inevitably depends on the judgements and assumptions of their authors.

Trade

Many, but not all, economists believe Brexit has had an adverse effect on UK trade.

Brexit fundamentally changed the UK’s trading relationship with the EU. The UK is now outside the EU single market and customs union. Although there are no tariffs on UK–EU trade in goods (provided certain conditions are met), other barriers to trade are now higher. Many commentators believe these have had a negative effect on trade.

The OBR assumes that Brexit will lead to a 15% reduction in UK exports and imports in the long run. This is not a 15% fall in absolute terms, but relative to a hypothetical scenario where the UK stayed in the EU. The OBR believes that post-Brexit free-trade agreements, such as with Australia and India, will have only a marginal impact.

Other analysts, such as Goldman Sachs and Professor Jonathan Portes of Kings College London, reach broadly similar conclusions.

Some commentators, including Policy Exchange, argue that the impact of Brexit on UK trade has been exaggerated.

Over the last decade, the UK’s trade performance has been much better in services than in goods. For further information, see the Commons Library briefing on UK-EU trade. This provides statistics on exports and imports since 2016.

UK–EU reset since July 2024

After taking office in July 2024, the Labour government in the UK launched a reset in UK–EU relations, seeking closer cooperation in several areas including security and defence and on a proposed UK–EU agreement on food and agricultural standards intended to reduce border checks on goods. This resulted in the UK and the EU agreeing a set of texts at the UK–EU summit in May 2025, including on a new strategic partnership, a security and defence partnership, and a set of commitments to work towards closer cooperation in other areas.

In December 2025, the UK and the EU also announced that they had agreed on terms for UK participation in the EU Erasmus+ youth and student mobility programme. They also said they were aiming to reach agreements on a UK–EU youth experience scheme, food and agricultural standards, and linking emissions trading systems by the time of the next UK–EU summit in 2026. They also said they would start negotiations on the UK’s participation in the EU’s internal electricity market.

The UK and the EU announced on 16 June 2026 that the 2026 summit would be held on 22 July. However, following Keir Starmer announcing his resignation as Prime Minister on 22 June, the summit was postponed. The UK–EU summit is now expected to take place in autumn 2026.

Hamish Falconer, who was appointed as Minister for European Relations in Andy Burnham’s government in July 2026, said in an interview in August 2026 that he wanted “a sense of renewed pace” in the reset discussions and “a deeper […] more ambitious relationship with the EU”.

Andy Burnham has said he wants his government to consolidate the progress made in the previous UK–EU negotiations and “make further progress quickly”. Mr Falconer said that the government will maintain the “red lines” set out in the Labour Party’s 2024 election manifesto. This said that there would be “no return to the [EU] single market, the customs union, or freedom of movement” under a Labour government.

Further information

For further information on the UK–EU reset and the May 2025 summit commitments, see the Commons Library briefing The UK–EU reset: Next steps after the May 2025 summit.

For an update on the reset published in November 2025, see the Commons Library briefing The 2026 review of the Trade and Cooperation Agreement and the UK-EU reset.

For information on the agreement on UK Erasmus+ participation and the joint UK–EU statement on reset progress in December 2025, see the Commons Library briefing UK-EU reset: Agreement on UK participation in the EU Erasmus+ programme.