The Prime Minister, Andy Burham, has suggested the UK could rejoin the EU (Image: Getty)
Britain would be hit with an instant £1trillion bill in new liabilities if it rejoined the European Union in time for the bloc’s next long-term budget, a leading Brexit analyst has warned. Tax consultant and longstanding Brexiteer Bob Lyddon argued that becoming a co-guarantor once more of the debts of the European Union and the European Investment Bank would impose an “unnecessary penalty” on the UK.
The figure, equivalent to 34% of the size of the British economy, would land on day one of membership for the 2028-34 Multiannual Financial Framework, Mr Lyddon suggested. He outlined his detailed analysis in an op-ed published on the Lyddon Consulting website. He issued the warning as the Prime Minister, Andy Burnham, signalled he is prepared to “go all the way” and reverse Brexit.
The Labour leader told the BBC that full EU membership remains one of the options on the table alongside a customs union or single market deal, insisting the country cannot leave the question “hanging” after a decade of drift.
Mr Lyddon told the Express: “These added liabilities would amount to £1trillion if we rejoined the EU for the start of the EU’s 2028-34 budget period.
“From there the only way is up, as the EU plans to spend and borrow much more during 2028-34: on accession countries like Serbia and Moldavia, on Ukraine, on sustainable projects around the world, but with a diminishing portion being spent in net contributor EU member states like Germany – and the UK if Burnham has his way.”
His warning centres on a new EU funding mechanism known as “national and regional partnership plans”. These plans are set to reshape how money from the bloc’s budget is allocated, further weakening the link between what a member state pays in and what is spent back in its territory. Britain, as before, would be one of the two major net contributors rather than a net recipient. Under the new system, even less EU cash would flow back to the UK than in the past.
Get the latest politics news – straight from our team in Westminster and more
Invalid email
You agree you are 18 or over. We use your sign-up to provide content in ways you’ve consented to and to improve our understanding of you. This may include adverts from us and third parties based on our knowledge of you. You can unsubscribe at any time. More Info.
Mr Lyddon stressed that the £1trillion would sit on top of the UK’s existing £3trillion public sector net debt. It forms part of a growing stock of “shadow” liabilities — guarantees, future spending commitments and contingent risks that do not appear in the headline national debt figures but ultimately fall on businesses and taxpayers.
The EU’s plans for 2028-34 already point to higher spending and borrowing. Accession countries, support for Ukraine and global green projects will take a larger share, while traditional net payers such as Germany and, potentially, a rejoined Britain would shoulder more of the burden with less return.
Mr Lyddon added: “This is the upshot of a new concept being introduced for the 2028-34 Multiannual Financial Framework called ‘national and regional partnership plans’.
“This is a new way of allocating funds from the EU Budget and one that is likely to further reduce the correlation between how much money a member state pays in, and what EU funds are spent in it.
Get top stories from The Express sent straight to your phone Join us on WhatsApp
Our community members are treated to special offers, promotions, and adverts from us and our partners. You can check out at any time. Read our Privacy Policy
“The UK, as before, would be one of the two major EU economies who would pay into the EU on net basis, rather than receiving. Under ‘national and regional partnership plans’ we will get even less EU money spent here than was the case before.
“It is all downside, and at a time when the UK is already skirting on the edge of bankruptcy.”
Mr Burnham’s comments at the Labour conference and in subsequent interviews have reopened the Brexit wars. French President Emmanuel Macron responded with a public “Welcome back,” while Spanish Prime Minister Pedro Sanchez said Spain would open its arms. Opposition figures and Brexiteers have accused the Prime Minister of preparing a full reversal of the 2016 referendum result.
Mr Lyddon’s analysis lands as the Government expands its own “shadow” liabilities through infrastructure, industrial and clean energy strategies. He argued the combination of domestic shadow debt and a return to EU co-guarantor status would create a “monstrous” total burden on British businesses and individuals.
Mr Lyddon, who has tracked EU finances for years and previously calculated that Brexit spared the UK from hundreds of billions in earlier shadow debts, said the £1trillion exposure would arise mainly from joint and several liability for EU borrowing and European Investment Bank obligations. Membership would also lock the UK into rising cash contributions as a large net payer, he suggested.
Mr Burnham has insisted any decision on the long-term relationship with Europe will be based on what is “doable” and where consensus can be found, with options due to be set out around a UK-EU summit later this year.
Brexit Chaos as Expert Warns Rejoining the EU Could Leave Britain Facing an Extra £1 Trillion in Financial Liabilities
Britain’s increasingly heated debate over its future relationship with the European Union has taken a dramatic turn after a financial analyst warned that rejoining the bloc could expose the UK to an estimated £1 trillion in additional financial liabilities.
The warning comes as Prime Minister Andy Burnham has reopened the debate over Britain’s long-term relationship with Brussels, arguing that Brexit has caused more harm than good and that the country should consider a range of options, potentially including full EU membership.
But the enormous figure cited by financial analyst Bob Lyddon has raised questions about the potential costs of reversing Brexit. In a report published in October 2026, Lyddon argues that returning to the EU in time to participate in its 2028–34 budget cycle could expose Britain to substantial additional financial commitments, including liabilities associated with EU borrowing and spending programmes.
The estimate is striking, amounting to roughly a third of the UK’s annual economic output. However, it is important to understand what the figure represents: it is an estimate of potential financial liabilities under a particular scenario, not an agreed bill that Britain has been presented with or a confirmed amount that would automatically become payable on rejoining.
Nevertheless, the warning has added a new dimension to the Brexit debate, forcing politicians and voters to confront a difficult question: what financial obligations would accompany a return to the European Union, and would the economic benefits justify the cost?
The £1 trillion warning explained
Lyddon’s analysis focuses on what he describes as the UK’s potential exposure to the EU’s financial liabilities if Britain returned to membership and participated in the bloc’s next multiannual financial framework, covering the years from 2028 to 2034.
His argument is that EU membership would involve more than annual contributions to the European budget. It could also bring exposure to financial commitments, guarantees, borrowing arrangements and other liabilities associated with EU programmes.
The report estimates that these additional, largely non-cash liabilities could total approximately £1 trillion under the scenario examined.
That distinction matters. A financial liability is not necessarily an immediate cash payment. Some liabilities represent guarantees or obligations that may only result in expenditure if particular circumstances arise. Others relate to future commitments or potential losses. The amount ultimately paid can therefore differ substantially from the headline value of the liabilities recorded.
The estimate also depends on assumptions about the terms of Britain’s hypothetical return, the EU’s future budget and the way shared financial obligations would be allocated.
Britain has not applied to rejoin the EU, and no accession agreement exists that would establish its precise financial responsibilities. Any actual negotiations would need to determine the terms of membership, including the UK’s budget contribution and treatment of relevant liabilities.
Consequently, the £1 trillion figure should be understood as a warning based on a particular financial model rather than a settled forecast of the cost of rejoining.
Even with that qualification, the underlying issue is significant. Any government considering a major change in Britain’s relationship with the EU would need to examine the financial implications carefully before making a commitment.
Why the EU membership debate has returned
The renewed discussion follows Burnham’s recent comments about the consequences of Brexit and the need to reconsider Britain’s long-term relationship with its largest nearby trading bloc.
Burnham has indicated that the government should assess several possible arrangements, ranging from maintaining the current relationship to closer cooperation through a customs union or single market, with full EU membership also among the options to be examined.
This represents a significant shift in the political conversation. Labour had previously ruled out rejoining the single market and customs union during the 2024 general election campaign. The renewed debate therefore raises questions about how far the government might be prepared to move beyond its existing policy.
Supporters of a closer relationship with Brussels argue that leaving the EU introduced additional barriers to trade, increased administrative burdens for some businesses and made it harder for British companies to operate seamlessly across European markets.
The Office for Budget Responsibility has estimated that the post-Brexit trading relationship will reduce the UK’s long-run productivity by around 4 per cent compared with remaining in the EU. That is a long-term economic estimate, rather than a measurement of the precise amount Britain has already lost, and it does not establish that full membership would automatically reverse every effect.
Nevertheless, proponents of closer integration believe that reducing trade friction could support investment, improve commercial relationships and create opportunities for economic growth.
Opponents counter that those potential gains must be weighed against membership contributions, regulatory obligations, freedom-of-movement arrangements and the political compromises involved in returning to the bloc.
The £1 trillion estimate has intensified that disagreement by focusing attention on a financial risk that supporters of rejoining would need to address.
Could Britain really be responsible for EU debts?
One of the central arguments in Lyddon’s analysis concerns the EU’s existing and future financial commitments.
The European Union operates a common budget and uses a range of financial instruments to support infrastructure, regional development, research, industrial programmes and other priorities. Some initiatives also involve borrowing or guarantees designed to mobilise investment.
Lyddon argues that a returning Britain could face a share of liabilities connected with these arrangements. He also warns that the EU’s proposed 2028–34 budget framework could expand spending commitments and financing requirements.
However, the existence of EU borrowing does not mean that a new member would automatically become responsible for every outstanding obligation in proportion to its economic size. The precise treatment of existing debt, guarantees and other commitments would depend on the applicable rules and the terms agreed during accession negotiations.
Britain’s previous membership also provides an important point of comparison. Before Brexit, the UK contributed to the EU budget under an established financial framework, while benefiting from various EU programmes and arrangements. After leaving, it remained responsible for certain obligations under the Withdrawal Agreement.
The European Commission’s 2026 budget documentation illustrates that the UK continues to make payments associated with outstanding pre-2021 commitments and its share of specified liabilities, including pensions and contingent financial obligations. Those payments arise from the existing withdrawal settlement, not from a decision to rejoin.
Any new membership agreement would need to address how Britain’s financial position differed from that of a country joining the EU for the first time, as well as what obligations would apply to future budgets.
The central question is therefore not simply whether the EU has debts. It is how a returning Britain would be expected to participate in the bloc’s financial system, and whether the resulting terms would be acceptable to the British government and taxpayers.
The potential economic benefits cannot be ignored
A balanced assessment must also consider what Britain might gain from closer integration.
The EU remains an important market for British businesses. Reducing customs procedures, regulatory barriers and other obstacles could make it easier for exporters to sell goods and services across Europe.
Supporters of rejoining argue that a more integrated trading relationship could encourage investment and improve productivity over time. They also point to cooperation in research, education, energy and security as areas where closer links might produce wider benefits.
The financial consequences of EU membership would therefore not be limited to payments made to Brussels. A full assessment would also need to consider the effects on tax revenues, economic activity, public services, business investment and household incomes.
However, those benefits are not guaranteed. They would depend on the terms of membership, the performance of the British and European economies, the response of businesses and the wider international environment.
Nor would rejoining necessarily restore every arrangement Britain enjoyed before Brexit without additional negotiations. The EU’s rules and budget priorities have evolved, and any future accession would have to be negotiated within the legal framework governing membership.
This is why the headline liability estimate, although substantial, cannot settle the debate on its own. It needs to be considered alongside credible estimates of the likely economic benefits and the costs of alternative arrangements.
What would happen to British taxpayers?
For taxpayers, the most important question is how any new financial commitments would affect public finances and government priorities.
If membership required larger contributions or exposure to additional liabilities, ministers would need to explain how those commitments would be managed alongside spending on the NHS, schools, transport, defence and other public services.
The government would also need to distinguish between payments that would be made every year and contingent obligations that might never result in a cash outflow.
Those differences are crucial when assessing the effect on borrowing, taxation and public spending. Treating every potential liability as an immediate bill would overstate the short-term cash cost. Ignoring contingent liabilities altogether, however, could understate the financial risks.
A credible analysis would therefore publish the assumptions behind the £1 trillion estimate, explain the likelihood and timing of potential payments, and compare them with the expected economic effects of different UK–EU arrangements.
It should also examine whether closer cooperation short of full membership could achieve some of the same economic objectives at a lower financial or political cost.
For example, a customs arrangement or agreements covering food standards, energy, research and youth mobility could reduce specific barriers without requiring the UK to return to every aspect of EU membership. Such arrangements would still involve trade-offs, and their value would depend on the precise terms agreed.
The political consequences of reopening Brexit
The debate also carries significant political risks.
Brexit remains a defining issue in British politics, with many voters viewing the 2016 referendum as a decision that should be respected and others believing that the economic consequences justify reconsidering the outcome.
For parties supporting Brexit, the prospect of returning to the EU creates an opportunity to demand detailed answers about costs, sovereignty, immigration and the authority of European institutions.
For advocates of closer ties, the discussion offers a chance to argue that Britain should prioritise economic cooperation with its nearest major trading partners.
But neither side can resolve the issue through a single dramatic figure or a general claim about economic damage. Voters need to understand the practical differences between full membership, participation in the single market, a customs union and the current relationship.
Each option would involve different obligations, advantages and limitations. Full EU membership would be a much more substantial change than improving existing trade and cooperation agreements.
If the government intends to examine all options, it will need to explain what each would mean in practice and how any major change would receive democratic approval.
A warning, not a final verdict
The claim that rejoining the EU could expose Britain to £1 trillion in additional liabilities has added an eye-catching financial dimension to an already divisive debate.
Lyddon’s analysis highlights a genuine issue: EU membership involves financial commitments beyond the visible annual budget contribution, and any government contemplating a return would need to understand those obligations in detail.
But the estimate is based on a particular scenario and should not be mistaken for a confirmed bill. The actual terms of any future membership would have to be negotiated, and the economic consequences would depend on more than the size of the liabilities alone.
Britain faces a choice about how closely it wants to cooperate with the European Union. Remaining outside the bloc, pursuing selective agreements or seeking full membership would each carry different economic, financial and political consequences.
The public deserves a transparent comparison of those options, including the potential costs, risks and benefits.
Ultimately, the most important question is not whether a £1 trillion figure can dominate the headlines. It is whether any proposed change would improve Britain’s long-term economic position, protect taxpayers and command sufficient public support.
Until the financial assumptions and the possible terms of membership are examined in detail, the warning should be treated as a reason for careful scrutiny—not as proof that rejoining would inevitably cost Britain £1 trillion.