We asked what impact measures such as the Green Book guidance had on major infrastructure projects like High Speed 2. The Department told us that departments were each responsible for ensuring that the projects within their areas remained below their overall emissions envelope and that it did not micromanage individual projects. It explained that in the case of the Department for Transport, the plans to achieve net zero would include a range of transport modes, from cycling, walking, cars, trains and planes, as well as core infrastructure projects such as HS2. It explained that this provided departments flexibility to balance their projects’ greenhouse gas emissions as if they went over on one project, the departments would need to find savings elsewhere.23