Structural interdependence shapes Brexit's uneven sectoral outcomes

Summary

Brexit’s campaign promises — border control, fishing sovereignty, manufacturing revival, and financial hub autonomy — produced uneven outcomes shaped by the depth of structural interdependence between UK sectors and EU markets.
Structural interdependence with EU supply chains and labour markets constrained sectors including manufacturing and fishing, where the absence of EU single-market access introduced non-tariff barriers and labour-mobility restrictions that domestic policy autonomy could not substitute.
The City of London’s institutional density — regulatory expertise, market infrastructure, and human-capital concentration — enabled adaptation to withdrawal by reauthoring its institutional character from “European financial hub” to “regulatory-divergence hub,” while production-embedded sectors lacking equivalent capital could not execute the same transformation.
The UK’s bargaining position was constrained by the Article 50 deadline, EU market-size asymmetry, and self-imposed red lines including the termination of freedom of movement, which foreclosed single-market membership and financial passporting as a consequence of chosen rather than fixed parameters.
Distributional asymmetries emerged: those principally affected by withdrawal-induced labour-mobility changes — including social care workers and the people they serve — were not the primary beneficiaries of the decision to leave.

Lede

Ten years after the 52%-48% vote to leave the European Union, the campaign’s four central promises — border control, fishing sovereignty, manufacturing renaissance, and a financial hub freed from Brussels regulation — have produced outcomes that diverge from pre-referendum rhetoric in ways traceable to identifiable structural causes. The divergence is not uniform across sectors: where institutional capital existed, adaptation occurred; where production was embedded in integrated supply chains and labour mobility, withdrawal-induced costs accumulated. Process-tracing analysis identifies the causal mechanisms through which these divergences operated, while place-reading reveals a temporal mismatch — the decade-scale embeddedness of material practice versus the electoral-cycle timescale of political re-narration — that produced material resistance rather than material transformation. Without counterfactual data on how these sectors would have performed under continued membership, the structural reading remains probabilistic rather than confirmed, but the pattern across sectors consistently points toward structural interdependence as the binding constraint.

Manufacturing — the Sunderland case

The manufacturing picture centres on Nissan’s Sunderland factory, a site whose character was authored over four decades of integrated European production. The workforce, supply chain, logistics network, and regulatory frameworks were all constructed around duty-free component flows and tariff-free exports to EU markets. The factory’s output fell from 507,000 cars in 2016 to 273,000 in the most recent year — a decline that embodies the tension between the 61% leave vote, which represented a political reading of the place, and the material reading of what the place was built to do.

Process-tracing identifies competing causal hypotheses, classified by diagnostic power. The structural-interdependence hypothesis holds that the depth of interdependence between UK manufacturing and EU markets was sufficient that withdrawal itself — irrespective of terms — would produce observable decline. The non-tariff barriers introduced by the Trade and Cooperation Agreement, which avoided 10% no-deal tariffs but created barriers with no prior equivalent, constitute a hoop test this hypothesis clears. The inadequate-negotiating-terms hypothesis suggests a differently structured agreement could have preserved benefits, but the smoking-gun test — comparative data showing the same factory’s performance under a counterfactual agreement — does not exist and constitutes the most diagnostic piece of evidence not currently available.

The inadequate-compensatory-mechanisms hypothesis specifies the mediating process: Nissan received £61m in state aid (details undisclosed for more than two years), followed by £101m in late 2022, with additional support under discussion. Substantial compensation required to maintain rather than increase output suggests a structural gap negotiation terms alone could not close. Nissan warned privately that being “left out of the latest batch of EU rules could create another ‘existential threat’” — a smoking-gun test for the hypothesis that regulatory divergence imposes costs, since a rational firm would not issue such threats unless it assessed real financial exposure from regulatory misalignment.

The potential Chery partnership with the Sunderland factory, if confirmed, would preserve existing jobs rather than restore former scale. Brian Gu, the vice-chair of Chinese carmaker Xpeng, stated that when looking to manufacture in Europe, “We will probably want to focus on the largest market first. The EU is one big market.” This observation highlights the structural logic constraining location-of-production decisions — market-size advantage — more decisively than bilateral state aid can offset.

The global-shocks hypothesis — that the pandemic, Ukraine energy crisis, Trump-era deglobalisation drive, and Nissan’s own restructuring (20,000 global job cuts) would have produced similar declines under continued membership — constitutes straw-in-the-wind evidence, individually weak. Systematic comparative data from comparable EU member states would be required to sustain this hypothesis against the sector-specific withdrawal mechanisms the other hypotheses identify. The baseline difficulties interacted with withdrawal costs: pandemic-era disruption and energy shocks made the marginal cost of non-tariff barriers more punishing, and ongoing regulatory uncertainty chilled investment.

Fishing — broken commitments and asymmetric bargaining

The fishing sector’s outcome illustrates the gap between pre-referendum promises and negotiated equilibrium. More than 9 in 10 fishers told pollsters they intended to vote leave. The sector makes up approximately 0.3% of the British economy but played an outsized role in the campaign.

The central bargaining interaction can be modelled as a game with asymmetric outside options. Britain imported £4.1bn of seafood last year, double the value of its exports (£2bn), according to Seafish. This trade imbalance meant any credible UK threat to unilaterally close waters to EU vessels would invite retaliatory measures imposing costs exceeding the domestic gains of exclusive access — a condition that made the pre-referendum promise to “take back control” of waters cheap talk, because no prior commitment device had been activated to alter the underlying asymmetry.

Boris Johnson’s 2020 deal allowed EU boats to continue fishing six miles off the coast until 2025. Last year, Prime Minister Keir Starmer extended EU vessels’ access to British waters up to 2038 as part of his “reset” deal. Mike Cohen, head of the National Federation of Fishermen’s Organisations, said fishers were “enormously aggrieved”: “Given access to British waters was a valuable thing, we thought we’d be able to get something in return.” This captures the gap between pre-referendum expectation and equilibrium outcome — the extension followed backward-induction logic in which the EU held the threat of market closure while the UK lacked credible alternatives.

The UK distant waters fleet is now reduced to a single vessel, the Hull-based Kirkella, after the other boat was sold in 2022 when the UK’s whitefish quota was slashed during negotiations with Norway. The quota reduction occurred after leaving the common fisheries policy but without the negotiating heft collective EU membership provided — the physical trace of the gap between the pre-referendum commitment and the eventually negotiated settlement.

More restrictive post-Brexit immigration rules made it harder to recruit skilled overseas workers for crews. Derek Meredith, the owner of three fishing boats at Brixham in Devon, stated: “Nothing changed with Brexit.” The place-reading is instructive: Brixham harbour’s working character was shaped by decades of European fishing policy; the promised reassertion of sovereignty was a narrative reading of what the place could become, and the decade delivered extended access for European vessels, a collapsed distant-waters fleet, and Meredith’s assessment.

Social care illustrates most clearly the mediating mechanism through which structural-interdependence costs were realised. The “toxic” debate, as Nadra Ahmed, chair of the National Care Association, recalled, sent a message of unwelcome to EU care workers that preceded any legal change: “I think for six months before the referendum, we started to see this disquiet amongst our European colleagues.” The exogenous negative signal raised the reservation wage of EU care workers, compressing recruitment before any legislative mechanism took effect.

EU worker numbers fell; vacancies in England rose from 78,000 in 2016-17 to 132,000 five years later. Kieran McCormick, who runs a recruitment agency for nurses and care workers across Northern Ireland, stated: “We have seen the volume of European healthcare workers coming to work for us fall off the face of the earth.” Raj Sehgal, who operates six care homes in rural Norfolk, stated: “It just became impossible: we weren’t getting the applications.”

In response, the government permitted overseas recruitment from non-EU countries in 2022. Annual health and care visa applications peaked at 161,600 in the year ending November 2023, with one in three new starters recruited from abroad. The Conservatives subsequently tightened rules, and Labour later effectively ended overseas recruitment of care workers — a pattern suggesting reactive, politically contingent compensation rather than structurally embedded support.

McCormick stated: “We don’t have a sufficient workforce to meet demand.” Sehgal, casting around for overseas student applicants, found “the calibre of applicants is not the same.” The distributional asymmetry is the most durable finding in this sector: those principally affected by withdrawal-induced labour-mobility changes were not those who voted for the outcome but those they were employed to serve. The question of how these sectors would have performed under continued membership cannot be answered from available data alone, but the vacancy trajectory — rising steeply from a pre-withdrawal baseline and remaining elevated through successive policy oscillations — is consistent with the structural-interdependence and inadequate-compensatory-mechanisms hypotheses.

City of London — institutional density enables adaptation

Before the referendum, executives warned that bankers would flee to continental hubs. Estimates projected up to 75,000 City jobs and as much as £10bn in tax revenue lost. Actual losses according to EY’s final Brexit tracker report in 2022: approximately 7,000 positions. About 1.1 million people remain employed across the City.

Miles Celic, chief executive of TheCityUK, recalled meeting then-Brexit minister David Davis in October 2016: “[Davis] listened very politely and at the end of it, he said: ‘I’m not worried about your industry, your industry is big enough and smart enough to look after itself.’ And that pretty much was what we subsequently saw.” The government’s inaction left the sector to compensate through internal reorganisation — regulators scrapped banker bonus caps and loosened listing rules, effectively re-authoring the regulatory framework.

The City possessed institutional resilience — regulatory expertise, market infrastructure, human-capital density — that enabled adaptation to new rules rather than dependency on prior arrangements. Manufacturing and fishing, embedded in value chains where UK policy autonomy could not substitute for market access, lacked this capacity. The skyscraper 22 Bishopsgate, put on ice just before the vote, was restarted after four months and completed in 2020 — its sunk cost serving as a commitment device that made sudden flight non-credible.

The City’s adaptation represents recharacterisation from “European financial hub” to “regulatory-divergence financial hub” — institutional density enabled this re-authoring; less capital-intensive sectors could not execute the same transformation. This outcome should not be mistaken for net gain: no expansion is claimed, only that the predicted collapse did not occur. Where benefits were realised, they concentrated in sectors possessing institutional density to adapt independently, confirming the structural logic distinguishing capital-dense from production-embedded sectors.

Border and travel — accumulating frictions

The post-Brexit border crossing is now a place where the promise of “taking back control” is experienced as an accumulation of small frictions. About 70% of the 54m UK passports in circulation are now navy blue; about 70m of the 90m annual UK overseas trips are made to Europe. Passport holders share a lane with non-EU visitors; blue passports get stamped every time.

The border has thickened: it is a seam where legibility is compromised by variable wait times and technical disruptions under the EU’s entry-exit system, which requires biometric data collection at the point of crossing. Even where most people experience little delay, effects ripple through travel patterns — Greece announced an exemption for UK travellers this summer, seeing bookings bounce compared with Portugal or Spain. When Etias is introduced, Britons will face a €20 charge to visit the EU — converting bureaucratic friction into direct financial cost levied on the exercise of movement.

The most telling statistic is the surge in demand for Irish passports — up 2,500% since the year before the referendum. Those with qualifying foreign ancestry have reacquired the document that restores prior border affordance, in effect opting out of the reduced prospect the blue passport now encodes.

Strategic negotiation structure

The Brexit negotiation was a sequential game constrained by three factors of distinct character. The two-year Article 50 deadline imposed time pressure asymmetrically on the departing party. The size differential — approximately 70 million UK versus approximately 450 million EU single market — concentrated bargaining leverage on the European side. The UK’s self-imposed red lines, particularly the termination of freedom of movement, were chosen constraints rather than fixed parameters of the negotiation.

The distinction matters. The Article 50 deadline and market-size differential were structural; the red lines were policy choices. The termination of freedom of movement foreclosed single-market membership and passporting — a consequence of a chosen constraint, not an unavoidable feature of departure itself. A differently specified negotiating mandate — preserving freedom of movement in exchange for single-market access — could have altered the bargaining range and, with it, the financial-services passporting regime and supply-chain friction terms.

A longer transition period would have prolonged adjustment rather than enabled it: sectors dependent on integrated supply chains and labour mobility would have faced the same frictions at a later date. The time-compression of the negotiation amplified the asymmetry between the structural and chosen constraints.

Temporal mismatch — material versus political timescales

Each place examined in this analysis — the factory floor, the fishing harbour, the City, the border crossing — has a character shaped by years of embedded practice: European supply chains integrated into production, fishing rhythms negotiated under common quotas, institutions calibrated to single-market regulation. Brexit proposed to re-author the character of these places through political act.

The distinctive analytical yield of this reading beyond process-tracing is a temporal mechanism: the mismatch between the decade-scale embeddedness of material practice and the electoral-cycle timescale of political re-narration explains why declarations of sovereignty could not re-author production realities within the observed period. The material character of these places was authored over decades; the political act to re-author them was compressed into months. The observed pattern — material resistance rather than material transformation — is what this temporal mismatch predicts.

The material character of Sunderland’s factory, Brixham’s harbour, and the City’s institutions was shaped by decades of European integration. The decade delivered not transformation but resistance — not because the places cannot change, but because sovereignty declarations operate on a timescale that cannot overwrite decade-scale embedded practice within a single electoral cycle. The gap between the political promise and the material outcome is not incidental but structurally determined by the timescale differential.

Convergent finding

Process-tracing identifies causal mechanisms varying across sectors in ways that predict observed outcomes. Where institutional density existed — most clearly in the City of London — adaptation occurred through internal reorganisation. Where production was embedded in integrated supply chains and labour mobility — manufacturing and fishing most visibly, social care in its workforce dimension — withdrawal-induced costs accumulated in ways that compensatory mechanisms addressed reactively and incompletely.

The distributional pattern is consistent: sectors with institutional capital adapted; production-embedded sectors experienced costs concentrated on populations whose mobility was reduced. The distributional asymmetry between those who voted for withdrawal and those who bear its labour-market costs remains, a decade on, unresolved.

The absence of counterfactual data — how these sectors would have performed under continued membership — means the structural reading cannot achieve full confirmation from available evidence alone. The pattern across sectors is sufficient to shift probability weight toward the structural-interdependence hypothesis and its mediating compensatory-mechanism failure, but the doubly decisive test remains unavailable. The convergence of sector-specific evidence, however, is consistent with the reading that withdrawal’s sectoral costs were structurally determined rather than negotiable.

Analytical techniques used in this piece

This analysis applies the methods below. Each links to a short, plain-English explainer you can read and reuse.

Genius Loci — Sense of Place: Reads the character and felt quality of a place.
Process Tracing: Reconstructs the step-by-step causal pathway of a specific historical event.
Strategic Interaction (Game Theory): Models a situation as a game — players, moves, payoffs, and likely equilibria.