British Prime Minister Andy Burnham has opened the possibility of Britain eventually returning to the European Union, saying the Government should examine the full range of options for its future relationship with Brussels. The debate reaches beyond Britain because New Zealand's trade agreement with the UK, CPTPP relationship and broader Commonwealth ties were all developed in a strategic environment partly shaped by Britain's post-Brexit independence.
INR Report: Based on reporting by RT, with additional verification from Reuters, the UK Government and the Office for Budget Responsibility HERE
British Prime Minister Andy Burnham has reopened one of the most consequential constitutional questions in modern British politics, saying his Government should consider options ranging from retaining the existing Brexit settlement to closer participation in European structures and, potentially, returning to the European Union.
Reuters independently reported Burnham's comments on September 30, confirming that the Prime Minister said Britain should consider its future relationship with the EU, including the possibility of rejoining. Burnham characterised Brexit as having done "more harm than good" and said the Government should examine what arrangements are realistically available. Reuters
That does not mean Britain has decided to rejoin the EU. It means an option that British governments had largely treated as politically closed following the 2016 referendum has returned to mainstream government consideration.
What Britain Actually Voted For
The 2016 referendum produced a 52 percent vote to leave and 48 percent to remain. Britain formally left the European Union on 31 January 2020 and departed the EU single market and customs union at the end of that year.
Brexit transferred significant areas of decision-making from EU institutions back to the British Government and Parliament. Britain regained an independent trade policy, ended automatic EU freedom of movement and acquired greater autonomy over immigration, regulation and international commercial agreements.
The consequences were more complicated than either side's referendum slogans suggested.
Ending EU freedom of movement did not automatically produce lower total migration because migration from outside Europe subsequently increased. Leaving the single market also introduced customs declarations, rules-of-origin requirements and other barriers to trade with Britain's largest neighbouring market.
At the same time, Britain gained the ability to negotiate trade agreements independently of the EU. That included agreements with Australia and New Zealand and accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, or CPTPP.
The central question therefore remains much the same as it was in 2016: how should Britain balance economic access to its largest neighbouring market against national control over laws, borders, regulation and trade policy?
The Economic Argument Is Not as Simple as a Headline Number
One of the strongest arguments advanced for closer EU integration is economic.
Britain's independent Office for Budget Responsibility continues to assume that Brexit will reduce the trade intensity of the UK economy by approximately 15 percent over the long term compared with remaining in the EU.
The OBR has also modelled a corresponding reduction of around 4 percent in potential productivity relative to a counterfactual in which Britain remained an EU member. Importantly, these figures are modelling assumptions about what the British economy might otherwise have become, rather than measurements showing that British GDP literally fell by those percentages after Brexit.
That distinction matters.
Britain's post-Brexit economy has simultaneously passed through the Covid-19 pandemic, global supply-chain disruption, sharp energy-price movements, inflation, higher interest rates and the economic consequences of the Russia-Ukraine war. Separating those effects from Brexit is therefore difficult.
The economic argument for reversing Brexit consequently depends not only on whether trade barriers impose costs, which they plainly can, but on what political and regulatory concessions Britain would have to make to remove them.
Rejoining Would Not Restore the Britain of 2015
A future application to rejoin the European Union would also be fundamentally different from simply cancelling Brexit.
Britain could not assume that the membership arrangements it previously enjoyed would automatically return. Any application would require negotiation with EU institutions and approval through the accession process.
That makes the real question substantially larger than whether Britain regrets Brexit.
The terms would matter.
Britain previously possessed important arrangements and opt-outs accumulated over decades of membership. Any future British government contemplating re-entry would therefore have to establish what Brussels was offering and what authority Britain would again agree to exercise collectively through European institutions.
Only then could voters meaningfully compare the economic benefits claimed for renewed integration against the sovereignty surrendered in obtaining them.
Britain Has Already Been Moving Closer to Europe
The political discussion about rejoining the EU is occurring after Britain and Brussels have already begun rebuilding substantial institutional links.
In May 2025, the UK and EU established a formal Security and Defence Partnership. It created mechanisms for regular strategic consultation and cooperation covering Ukraine, Russia, sanctions, maritime security, military mobility, defence industries, cyber threats, critical infrastructure and other security matters.
The British Government's own agreement describes the UK and EU as sharing responsibility for European security and provides for six-monthly foreign and security policy dialogues.
The wider UK-EU Strategic Partnership agreed in 2025 also committed both sides to deeper cooperation extending beyond defence.
Britain therefore never became strategically detached from Europe after Brexit. The emerging question is how far economic, regulatory and political reintegration should now accompany that security relationship.
Sovereignty Remains the Unavoidable Question
This is where the Brexit argument returns to its starting point.
Membership of the European Union provides participating states with access to an enormous integrated market and influence over common European rules. It also requires those countries to exercise parts of their sovereignty collectively through EU treaties and institutions.
Supporters of closer integration argue that shared rules can increase trade, investment and geopolitical influence.
Supporters of Brexit counter that democratic control over borders, regulation, trade policy and legislation has value even where exercising that independence creates economic friction.
Those are competing political priorities rather than a question that can be settled by one economic statistic.
Burnham's intervention is significant because it indicates that the British Government is prepared to examine that trade-off again.
Does This Affect New Zealand?
It potentially does, particularly if Britain's reconsideration progresses from political discussion to formal negotiations.
New Zealand's relationship with Britain changed materially after Brexit. Once Britain recovered an independent trade policy, London and Wellington negotiated the New Zealand-United Kingdom Free Trade Agreement, which entered into force in 2023.
Britain subsequently joined CPTPP, connecting it more directly with New Zealand and other Pacific economies through a major trade framework outside the EU.
A British return to the EU would therefore raise practical questions for New Zealand about how Britain's existing independent trade commitments would interact with EU membership. The consequences would depend entirely on the eventual terms and could not be assumed in advance.
There is also a wider strategic lesson.
Brexit demonstrated that a country can place political sovereignty, regulatory independence and national decision-making alongside conventional measures of economic efficiency when deciding how deeply it integrates with larger international institutions. Britain's experience since leaving demonstrates the other side of that equation: autonomy can also produce transaction costs, trade barriers and difficult policy choices.
For New Zealand, a geographically isolated trading nation that simultaneously participates in CPTPP, maintains agreements with Britain and the European Union, and depends heavily on international markets, that balance between access and autonomy remains highly relevant.
Britain may therefore be reopening more than the question of Brexit.
It is reopening the underlying debate over how much national independence countries are prepared to exchange for the economic and strategic advantages of deeper international integration.
Independent reporting. Original context. Credited sources.
Sources
RT, 30 September 2026: UK may reverse Brexit – Burnham
Reuters, 30 September 2026: Burnham says UK should weigh post-Brexit EU options, including rejoining
UK Government: UK-EU Security and Defence Partnership
UK Government: UK-EU Summit Joint Statement
Office for Budget Responsibility: Economic and Fiscal Outlook, November 2025
New Zealand Ministry of Foreign Affairs and Trade: New Zealand-United Kingdom Free Trade Agreement