The Treasury has at last revealed the contents of an email sent to the then-Chancellor, Philip Hammond, about the high cost of the Net Zero emissions target following a protracted Freedom of Information dispute lasting almost 2 years.

In the email, The Treasury said: “The CCC estimate that meeting net zero will cost £50bn annually in 2050. BEIS [The Department for Business, Energy and Industrial Strategy] estimates put the figure at £70bn per annum. We consider the BEIS figure to be more realistic.”

The “more realistic” BEIS figure is the one that the government fought to withhold from publication, before a ruling by the Information Commissioner last month.

They also described Number 10 and BEIS as having “distanced themselves from the £1 trillion figure” and said they have been “following public lines” including “The Committee on Climate Change say this will cost £50bn annually in 2050.”

Speaking on Monday, the Prime Minister insisted his Net Zero agenda would not result in any new carbon taxes for consumers. He told The Sun he was planning “an agenda for an economic bounce back…”

The existence of internal government estimates of the cost of Net Zero had first been acknowledged in a leaked letter that appeared in the Financial Times in June 2019.

We now know that BEIS modelling estimated that the cost of Net Zero would amount to £1,275bn by 2050. The annual cost was modelled to rise from £15bn a year at present, to approximately £70bn in 2050. This is illustrated by a Treasury graph showing an increasing divergence with the CCC calculations.