Last reviewed: 7 October 2026
THE BREXIT FILES — Claim. Evidence. Outcome.
“Take back control” was not only about immigration or borders.
It was also about laws.
Throughout the 2016 referendum campaign, supporters of leaving the European Union argued that EU institutions were making important rules affecting Britain, that EU law could take priority over Acts of Parliament, and that the Court of Justice of the European Union could issue judgments binding on the UK.
Leaving the EU, they argued, would restore law-making power to Westminster.
That claim contained a substantial truth.
Brexit ended the general supremacy of EU law in the UK, removed the automatic flow of new EU law into most of the country, ended the Court of Justice’s general authority over UK law, and gave Parliament and UK governments much greater freedom to change regulations inherited from EU membership.
But the slogan also simplified something constitutionally complicated.
The UK Parliament had not literally stopped being sovereign while Britain was an EU member. EU law had effect in the UK because Parliament itself had passed the European Communities Act 1972.
And sovereignty after Brexit does not mean complete freedom from rules, treaties or economic consequences.
Britain still enters international agreements. Northern Ireland remains subject to particular EU rules under the Windsor Framework. British exporters must comply with the rules of markets they sell into. And the UK government is currently negotiating closer alignment with EU rules in some areas in exchange for reducing trade barriers.
So did Brexit return sovereignty?
Yes — in important legal and regulatory respects.
But sovereignty is not the same as total independence from other countries, markets or agreements.
The more useful question is what Britain has actually done with the additional freedom Brexit created.
What Did “Take Back Control of Our Laws” Mean?
The sovereignty argument was one of the central intellectual cases for Brexit.
Under EU membership, laws were made at several levels.
The UK Parliament continued to make domestic law.
But in areas where the European Union had competence, EU legislation could also apply.
Depending on the type of EU legislation, some rules applied directly while others required implementation through UK legislation.
Most importantly, where directly effective EU law conflicted with domestic law within the scope of EU competence, UK courts were required to give EU law priority.
That was one of the features Brexit supporters wanted to end.
The argument was therefore not that Parliament had stopped passing laws.
It plainly had not.
The argument was that Parliament did not have the final practical word in every area governed by EU law while the European Communities Act remained in force.
Was Parliament Sovereign Before Brexit?
This is where the debate becomes more subtle.
According to the traditional British constitutional doctrine of parliamentary sovereignty, Parliament has the legal authority to make or unmake any law.
The House of Commons Library explains that EU membership complicated that principle but did not simply abolish it.
The European Communities Act 1972 gave EU law domestic legal effect.
That meant British courts could, in areas covered by EU law, disapply conflicting provisions of domestic legislation.
The famous Factortame litigation demonstrated this.
To many Brexit supporters, that looked like a direct loss of sovereignty: a European legal rule could take precedence over legislation passed at Westminster.
But there was another constitutional interpretation.
Parliament had itself enacted the European Communities Act.
It had therefore voluntarily accepted the legal consequences of EU membership.
And Parliament retained the legal power to repeal that Act and withdraw from the European system — which is ultimately what happened.
The House of Commons Library describes EU law’s domestic priority as resting on the UK’s voluntary acceptance of EU obligations, and notes that Parliament later exercised its sovereignty by triggering withdrawal and repealing the 1972 Act.
So it is too simple to say:
“Britain had no sovereignty before Brexit.”
But it is also too simple to say:
“EU membership made no difference to parliamentary sovereignty.”
While the European Communities Act was in force, EU law had a special status in the UK legal system.
Brexit changed that.
House of Commons Library — Parliamentary sovereignty
What Changed When Britain Left the EU Legal Order?
The key legal change was repealing the European Communities Act 1972.
The European Union (Withdrawal) Act 2018 removed the domestic legal mechanism through which EU law had automatically taken effect in the UK.
After the post-Brexit transition period ended on 31 December 2020, the UK was no longer part of the EU’s general law-making system.
For Great Britain in particular, that meant:
- New EU legislation did not automatically become UK law;
- Parliament could legislate differently from the EU;
- UK ministers and regulators could design different domestic rules;
- The Court of Justice of the European Union no longer had general jurisdiction over UK law;
- The UK could pursue its own trade policy and regulatory approach.
Those are real changes in legal and regulatory autonomy.
The European Union (Withdrawal Agreement) Act 2020 explicitly recognises the UK Parliament’s sovereignty.
European Union (Withdrawal Agreement) Act 2020 — Section 38
Why Did Britain Keep Thousands of EU-Derived Laws?
If Brexit was about taking back control, some people expected EU rules simply to disappear.
That would have caused enormous legal disruption.
For almost five decades, EU-derived rules had become embedded across areas including:
- Product standards
- Employment law
- Environmental protection
- Agriculture
- Transport
- Financial services
- Consumer protection
- Food safety
- Workplace safety
Removing them all overnight would have created gaps across the statute book.
So the UK adopted a continuity approach.
The European Union (Withdrawal) Act copied or preserved a large body of existing EU-derived law so that the legal system would continue functioning after Brexit.
This became known as retained EU law.
Later legislation changed both its status and its name.
From 1 January 2024, much of the remaining body became known as assimilated law, and the general principle of EU law supremacy was removed from domestic law.
That means an EU origin does not make these rules foreign law imposed on Britain today.
They survive because UK law has preserved them.
And Parliament can change them.
Retained EU Law (Revocation and Reform) Act 2023
How Much EU-Derived Law Still Exists?
More than many people might expect.
The UK government’s final Retained EU Law and Assimilated Law dashboard, updated in July 2026, identified 6,921 individual pieces of retained or assimilated law across more than 400 policy areas.
By 23 June 2026, the government reported that 2,700 instruments had been revoked or reformed.
These figures require some caution.
Counting pieces of legislation does not tell us how economically or socially important each one is.
A minor technical regulation and a major regulatory framework each count as one item.
But the figures illustrate an important point.
Brexit did not remove Europe’s legal legacy from Britain.
Instead, it transferred responsibility for that legacy into the domestic legal system.
Britain gained the ability to change those rules, but governments have often chosen to keep them where continuity remains useful.
UK Government — Retained EU law and assimilated law dashboard
UK Government — Final Assimilated Law Parliamentary Report, December 2025 to June 2026
Was the Supremacy of EU Law Abolished?
For the general domestic legal system, yes.
The Retained EU Law (Revocation and Reform) Act 2023 states that after the end of 2023:
“The principle of the supremacy of EU law is not part of domestic law.”
That is a major constitutional change.
Domestic legislation now takes priority over assimilated direct EU legislation where the two conflict, subject to specific statutory exceptions and the UK’s continuing international obligations.
The Act also removed general principles of EU law from domestic law after the end of 2023.
So one of Brexit’s core legal objectives—ending the general supremacy of EU law—has been delivered.
Retained EU Law (Revocation and Reform) Act 2023 — Section 3
Does the European Court Still Control British Law?
Not generally.
The Court of Justice of the European Union no longer sits at the top of the UK’s ordinary legal system as it did when Britain was an EU member.
UK courts are no longer generally bound by new CJEU judgments when deciding domestic law.
But saying the European Court has no role whatsoever would also be inaccurate.
The Withdrawal Agreement created continuing legal obligations in specific areas.
The most important continuing exception concerns Northern Ireland under the Windsor Framework, where certain EU rules continue to apply.
So Brexit substantially reduced the CJEU’s role in the United Kingdom.
It did not erase every legal connection created by the agreements governing Britain’s withdrawal.
What About Northern Ireland?
Northern Ireland is the biggest qualification to any simple claim that EU law no longer applies within the United Kingdom.
The Windsor Framework — the revised form of the Northern Ireland Protocol — was designed to avoid a hard regulatory and customs border on the island of Ireland while protecting the EU Single Market.
As a result, Northern Ireland remains aligned with parts of EU law, mainly relating to goods.
Some of these rules operate through dynamic alignment.
That means when certain EU laws covered by the Framework are amended or replaced, the updated rules may also apply in Northern Ireland.
This is a genuine limitation on regulatory divergence within part of the UK.
Northern Ireland Assembly — EU Law and Northern Ireland
What Is the Stormont Brake?
The Windsor Framework introduced additional democratic safeguards.
One of them is the Stormont Brake.
Under specified conditions, 30 Members of the Northern Ireland Assembly from at least two parties can object to certain amended or replacement EU laws that would otherwise apply in Northern Ireland.
If the legal conditions are met, the UK government can prevent the updated rule from applying.
There is also a separate process for adding genuinely new EU laws to the Framework.
These mechanisms do not give Northern Ireland complete freedom from EU goods law.
But they do give elected representatives and the UK government a greater role than existed under the original Protocol.
House of Commons Library — The Stormont Brake in action
Does Brexit Mean Britain Can Now Make Any Rules It Wants?
Legally, Parliament has very wide law-making powers.
Practically, no modern country operates in isolation.
Britain belongs to the World Trade Organisation.
It signs trade agreements.
It participates in international treaties.
It cooperates on aviation, security, science, nuclear regulation and many other areas.
Every international agreement involves commitments.
That is not unique to the European Union.
The important distinction is that the UK now participates in most of these arrangements as a state outside the EU rather than as an EU member state.
It can choose whether to enter agreements.
But once it enters them, breaking the rules may have consequences.
That is sovereignty being exercised, not sovereignty disappearing.
What Does the UK-EU Trade Agreement Require?
After Brexit, Britain and the EU negotiated the Trade and Cooperation Agreement.
The agreement provides tariff-free and quota-free trade in qualifying goods, alongside cooperation in other areas.
It does not generally require Britain to copy EU law.
The House of Commons Library notes that the agreement recognises both parties’ right to regulate and does not aim to harmonise their rules.
However, it contains “level playing field” commitments covering areas such as:
- Labour and social standards
- Environmental protection
- Climate policy
- Subsidy control
- Competition
If major regulatory divergence materially affects trade or investment, the agreement allows rebalancing measures, potentially including tariffs, subject to dispute procedures.
So Britain can diverge.
But divergence can have a price.
That is one of the central realities of post-Brexit sovereignty.
House of Commons Library — UK-EU Trade and Cooperation Agreement: Level playing field
What About British Companies Selling Into Europe?
A British company exporting into the EU must meet relevant EU market rules.
Some describe this as Britain being forced to obey EU law after Brexit.
That is too broad.
If a British company wants to sell goods into the United States, it must comply with relevant US requirements.
If it exports to Japan, Japanese market rules matter.
The same applies to the EU.
The difference is economic scale and geography.
The EU remains one of Britain’s largest markets, so EU regulation has considerable practical influence over British businesses.
Some companies may decide it is cheaper to manufacture to one common standard rather than produce separate versions for UK and EU markets.
But commercial pressure to follow a foreign market’s rules is not the same as those rules automatically becoming Acts of Parliament.
Britain Is Now Choosing Alignment in Some Areas
The current UK-EU relationship provides perhaps the clearest illustration of what sovereignty actually means.
At the UK-EU Summit in May 2025, the British government and the European Union agreed to work towards a new Sanitary and Phytosanitary — or SPS — agreement covering areas such as food, animals, plants and agricultural products.
The proposed agreement is intended to reduce checks, paperwork and trade barriers.
But the planned mechanism involves dynamic alignment with relevant EU rules across the areas covered.
As of October 2026, negotiations are continuing, and UK government guidance says the agreement is intended to take effect in mid-2027, subject to the outcome of those negotiations.
Government guidance says that as relevant EU rules change, rules in Great Britain would update too, while the UK would contribute to the decision-shaping process.
This matters to the sovereignty debate.
Britain is outside the EU.
It has the legal freedom to maintain separate rules.
Yet the government is voluntarily negotiating alignment because it believes the economic benefits of reducing trade friction justify accepting common rules in this area.
That is not the same constitutional position Britain occupied as an EU member.
But it illustrates the trade-off between regulatory autonomy and market access.
UK Government — SPS agreement: preparing your business
So Was Sovereignty Really “Returned”?
In important respects, yes.
The UK can now make regulatory choices that would not have been possible while it was bound by EU membership.
Parliament has regained the ability to legislate contrary to EU rules across most areas without EU law taking automatic priority.
New EU legislation does not generally become UK law.
The UK has its own trade policy.
The CJEU no longer has general authority over British law.
The government can amend or repeal assimilated EU-derived rules.
These are meaningful constitutional changes.
But the language of sovereignty can become misleading when it suggests that independence means freedom from consequences.
Britain remains geographically beside the world’s largest integrated trading bloc.
It has treaty obligations.
Northern Ireland has unique arrangements.
Businesses respond to the rules of export markets.
And governments may voluntarily align regulations where they judge that economic benefits outweigh the value of regulatory difference.
What Brexit Changed — and What It Did Not
Brexit changed who has the final legal authority to decide across most areas of British law.
That matters.
But it did not abolish economic interdependence.
It did not abolish international law.
It did not mean every EU-derived rule would disappear.
It did not prevent future British governments from agreeing common rules with Europe.
And it did not turn sovereignty into a guarantee that every domestic policy choice would produce better outcomes.
Sovereignty is a power.
Whether using that power produces better regulation, stronger growth or more democratic accountability depends on the decisions governments make afterwards.
The Verdict
THE BREXIT FILES
Claim: Leaving the European Union would allow Britain to take back control of its laws and restore parliamentary sovereignty.
Evidence: During EU membership, EU law had priority in areas of EU competence because Parliament had given it domestic effect through the European Communities Act 1972. Parliament nevertheless retained the ultimate legal ability to repeal that framework and leave the EU.
Outcome: Brexit ended the general supremacy and automatic application of EU law, greatly reduced the role of the CJEU, and gave the UK much greater freedom to change domestic regulation. Thousands of EU-derived rules remain as UK “assimilated law”, Northern Ireland continues to apply specified EU rules under the Windsor Framework, and the UK continues to accept constraints through treaties and trade agreements.
Verdict: Substantially delivered in legal terms — but “sovereignty” never meant complete freedom from international commitments, economic trade-offs or voluntarily agreed common rules.
That is the distinction that matters.
Brexit did change Britain’s constitutional relationship with the European Union.
It is wrong to pretend otherwise.
But Britain was not a country without a sovereign Parliament before 2016.
Nor did leaving the EU create a world in which Britain could regulate without considering its neighbours, its trading partners or the agreements it chooses to sign.
Perhaps the clearest evidence comes from the current relationship itself.
Britain now has the legal power to diverge from EU rules in most areas.
It also has the legal power to align with them.
Sometimes governments will choose divergence.
Sometimes they will choose cooperation.
Sometimes they will exchange a degree of regulatory freedom for easier trade.
That is what sovereignty looks like in practice.
The real political question is no longer simply:
“Who has control?”
It is:
“What are we using that control to achieve?”