Since Brexit reshaped the terms of British commerce, a quieter toll has accumulated in the gap between regulatory regimes: the UK is estimated to be forgoing between £3.7bn and £6.5bn each year in EU exports simply because a product certified safe in Birmingham must be certified again in Brussels. The IPPR's analysis isolates this friction from pandemic disruption, energy shocks, and supply chain shifts, finding the testing standards barrier significant on its own. It is a reminder that the costs of political divergence are not always announced with drama — sometimes they arrive as revenue tha