UK imports and exports are 15% lower than they would have been had the United Kingdom remained in the European Union.

Omissions

• The 15% figure and the 4% productivity figure are the OBR's long-run modelling assumptions (calibrated to the average of external studies), not measured outcomes; the claim presents a forecast/counterfactual as an established fact ('so it has turned out to be').
• The counterfactual ('had the UK remained in the EU') cannot be observed, so all estimates depend on the chosen methodology; estimates range from the LSE study (total exports 6.4% and imports 3.1% lower by end-2022) to NIESR (16.9%/16.1%) and CER (16%/14%).
• Measured against the simple 2019 baseline rather than a counterfactual, the BBC reports that in 2025 UK exports to the EU were 14% down and imports 10% down on 2019 levels — a lower import figure than 15%.
• The EU's falling share of UK trade is partly driven by faster growth in the rest of the world, not only by Brexit-related frictions.
• The specific '15%' long-run figure was formalised in the OBR's April 2023 Brexit analysis and restated in later OBR publications; the empirical estimates above are from 2026 publications, i.e. the most recent data available before the session date.

Sources

• PrimaryOffice for Budget Responsibility (OBR) — 'How are our Brexit forecasting assumptions performing?'"On trade and productivity, we assume that the volume of UK imports and exports will both be 15 per cent lower in the long run than if we had remained in the EU" (with a corresponding 4 per cent reduction in potential productivity).
• SecondaryBBC News — 'Ten years on, Brexit's economic impact is becoming clearer'"Think tank Niesr calculates exports were 16.9% lower and imports 16.1% less than what could have been expected based on positive pre-2016 trends. The Centre for European Reform uses a different method ... leading to a goods trade hit of 16% to exports and 14% to imports." Also: "compared to 2019, 2025 UK exports to the EU were 14% down and imports were down 10%."
• SecondaryGLA Economics — 'Overview of recent studies on Brexit's economic impacts'"The Office for Budget Responsibility's (OBR) analysis of Brexit impacts suggested that 'the volume of UK imports and exports will both be 15 per cent lower than if we had remained in the EU. We assume that the resulting reduction in the trade intensity of GDP will lead to a 4 per cent reduction in the potential productivity of the UK economy'."
• TertiaryBrexit FactBase — 'Overall trade impact' (citing ONS March 2026 and CER June 2026)"The OBR continues with its long-held position ... that it expects Brexit to cause exports and imports to both fall by 15%." CER study (June 2026): "exports drop by 12% – goods by 16% and services by 7%; imports drop by 16% – goods by 14% and services by 19%."