Question to the Cabinet Office:

To ask the Minister for the Cabinet Office, whether his Department is conducting an assessment of the potential economic impact on the United Kingdom of joining the European Union's Single Market.

The Office for Budget Responsibility (OBR) is the government’s official forecaster. The OBR has included assessments of the economic impacts of leaving the EU in its forecasts since 2016. In March 2020 the OBR estimated that, as a result of the deal negotiated by the then government, GDP will be 4% lower in the long run than it would have been had the UK not withdrawn from the EU. As of the Spring Forecast 2026, these assumptions remain unchanged.