Rishi Sunak was accused of an eco own goal after hopes for a £230 million green town were scuppered.
The pioneering plan would have created the UK’s largest net-zero town five miles outside of Oxford.
But the government has torpedoed the idea - saying the homes aren’t required to meet the ambitious net-zero standards set by the council.
It comes despite Sunak’s pledge for Britain to reach net-zero by 2050 - a target which critics say the government needs to do more to meet.
Activists have filed a High Court claim against the decision, accusing it of blocking local efforts to tackle climate change.
Hugh Ellis, policy director at the Town and Country Planning Association, said: “The decision to scupper this development is a disaster for future generations.”
The eco-friendly development, called Salt Cross Garden Village, envisioned building 2,200 homes, two schools and a science park.
Nestled in countryside, it would have been powered through renewable sources like solar energy.
West Oxfordshire District Council, which drew up the plans, said the eco town would be worth £700million once completed.
It was intended to set a national example for future housing developments.
The council said it hoped to build an “exemplary garden village, creating a green, climate friendly, safe and inclusive new community”.
But government planning inspectors, consulted on major building projects, said the plans exceeded existing national policies.
They advised the council to amend the wording of its target for a net-zero development to reflect an ambition rather than a requirement.
Climate group Rights Community Action and law firm Leigh Day have filed legal papers at the High Court appealing the decision to water down the net-zero objectives.
Naomi Luhde-Thompson, director of RCA, said: “It’s not right that local communities working to tackle climate change are being prevented by the central government.
“Planning inspectors said the net-zero standards are ‘too high’, an incredible statement in the face of the climate disaster on our doorstep - and the Government’s environmental pledges.”
The government’s climate strategy, which was updated in March, has already come under fire from critics.
It has already committed to reaching net-zero greenhouse gas emissions by 2050 - a target required under the 2015 Paris climate agreement.
However, the government is not on track to meet that goal due to a lack of suitable policies, according to analysis by environmental think tank Green Alliance.
The Department for Levelling Up, Housing and Communities declined to comment due to the open legal action.
