Question to the HM Treasury:

To ask the Chancellor of the Exchequer, whether her Department has made a recent assessment of the potential impact of re-joining the EU Customs Union on the UK economy, in the context of the UK-EU summit on 19 May 2025.

The OBR has estimated that productivity will be 4% lower in the long run than it would have been had the UK not withdrawn from the EU, and that imports and exports will eventually both be 15 per cent lower than had we stayed in the EU. As of the Spring Budget 2025, these assumptions are unchanged from its previous assessment. The OBR estimated in their March 2021 Economic and Fiscal Outlook that two-fifths of this impact to productivity had already materialised before the Trade and Cooperation Agreement came into force in January 2021.

The Government is working with the EU to identify areas where we can strengthen cooperation for mutual benefit, such as the economy, energy, security and resilience. There will be no return to the Customs Union or the single market. But we are committed to finding constructive ways to work together and deliver for the British people.