Net zero is an all-encompassing challenge that will affect every part of government. It will not be achieved if it is not sufficiently prioritised when departments make decisions that could impact on greenhouse gas emissions.18 We asked whether other departmental priorities, such as building enough homes, could supersede net zero and if the Department had the power to overrule these decisions in favour of net zero. We also asked how net zero was being prioritised in decisions like the granting of North Sea oil and gas licences, which could send the wrong message to the public about Government’s commitment to net zero. The Department explained that achieving net zero relied on its system of collective ownership, which should ensure everyone acted in support of the overall goal, rather than one department directing all others. The Department expected that where departments consistently fall behind, they would be held to account through the new coordination arrangements, which run from the Prime Minister and the Cabinet Committees, to the relevant secretary of state and the department itself, to ensure necessary action was taken to achieve net zero. The NAO found that spending reviews, led by HM Treasury, will be crucial to achieving net zero, as they allocate budgets to departments in the medium term (typically three to five years) and will provide an opportunity to encourage a coordinated approach. The Treasury and Department agreed that an important change in the most recent spending review was including officials from the Department to help scrutinise departments’ bids to ensure they aligned with the wider net zero strategy.19