In the dying days of her premiership, Theresa May brought forward legislation to follow the advice of the independent Committee on Climate Change and set a net-zero carbon target for the UK for 2050. This follows the overwhelming vote in parliament for Britain to declare a “climate emergency.”

Yet in defiance of the prime minister, the government’s scientific advice, the clear will of parliament and – we shouldn’t forget – those tens of thousands protesting in recent months, later reports claimed that the Treasury was attempting to apply the brakes to Britain’s decarbonisation programme. Using the (spurious, but eye-catching) figure of a £1 trillion cost, Chancellor Philip Hammond was quoted warning the prime minister that tackling climate change would mean “less money would be available for schools, police, hospitals and other areas of public spending.”

If you wanted a story that summarised everything that was wrong with how the Treasury thinks about the environment, it’s all there: the defiance of government and parliament in the name of allegedly sound finance; the use of opaque figures based solely on its own authority; the leak to the press against the rest of government; the woeful failure to consider government spending as anything other than a zero-sum game; and above all else, the thoughtless weighting of allegedly “financial” concerns against all other objectives.

This report presents the case for reform of Britain’s main economic and financial ministry as a crucial part of delivering a UK Green New Deal in government. It argues that trust in government has decayed and that the Treasury’s own commitment to flawed metrics and a narrow focus on financial sustainability has contributed materially to this. The Green New Deal, interpreted here principally as the need to implement a rapid programme of decarbonisation that is socially just, could be the opportunity to restore that lost faith in government. Indeed this report argues that a transition may well be difficult to achieve on any other basis, and that the Treasury itself must now take a lead in its delivery.