Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, with reference to the oral contribution of the Minister for Nature Recovery and the Domestic Environment of 20 October 2021, Official Report, Column 843, if he will publish the methodology used in calculating that ending sewage outflows would cost up to £660 billion.

The figures referred to were from draft findings of the Storm Overflows Evidence Project, which was commissioned by the Storm Overflows Taskforce (made up of a range of active stakeholders in this sector). The final report considers a wide range of policies and scenarios with their respective cost and impact on customer bills, including the upper bound figure of £600 billion to separate the combined sewer network. This research was an independent report, conducted by Stantec, and is available here: https://www.gov.uk/government/publications/storm-overflows-evidence-project

The report contains detailed methodology of how it arrived at its initial conclusions and the government will consider its findings carefully, alongside other recommendations from the Storm Overflows Taskforce.