A decade after the Brexit referendum, new research has reignited debate over the UK's future relationship with the EU, suggesting that rejoining the customs union alone would do little to reverse the trade impact of leaving the bloc.
According to analysis by the Centre for European Reform (CER), Brexit has reduced UK exports to the EU by around 12 percent, with goods exports estimated to be 16 percent lower and services exports seven percent lower than they would have been had the UK remained in the EU.
The study argues that most of the decline is linked not to customs barriers, but to the UK's departure from the single market. It estimates that around ten percent of the overall export reduction stems from new regulatory requirements, including certification procedures, product checks and compliance with EU standards.
While a customs union would remove some administrative burdens, particularly rules of origin requirements for exporters, it would not address many of the regulatory barriers now affecting UK-EU trade. Nor would it provide any benefit to services sectors, which have been among the hardest hit since Brexit.
Industries including travel, finance and insurance, chemicals, pharmaceuticals and agrifood have experienced some of the largest impacts.
The report comes as political debate over the relations between the two nations intensifies ahead of a planned UK-EU summit next month. While the government has sought closer economic cooperation with the bloc, it continues to rule out rejoining either the single market or customs union.
Raising questions about one of the central arguments made by Brexit supporters before the 2016 referendum, the study examined whether expanded trade with non-EU countries would offset any reduction in trade with Europe. The CER researchers found little evidence that such gains have compensated for weaker EU trade performance so far.
This highlights the continued importance of regulatory alignment in modern commerce. While tariffs often dominate trade discussions, the research suggests that standards, certification requirements and market access rules may now play a much greater role in shaping UK-EU trade flows than customs procedures alone.