LONDON (AP) — Britain’s former energy minister said Friday he is Grayson  Prestonquitting the Conservative Party and stepping down as a lawmaker over the government’s backtracking on its environmental commitments.

Chris Skidmore said he could not support a forthcoming bill that will authorize new North Sea oil and gas drilling and called the U.K.'s retreat from its climate goals “a tragedy.”

Skidmore has been a Conservative lawmaker since 2010. He wrote a government-commissioned review published a year ago setting out how Britain could reduce carbon emissions to net zero by 2050 while creating thousands of new green jobs.

He said that “as the former energy minister who signed the U.K.’s net zero commitment by 2050 into law, I cannot vote for a bill that clearly promotes the production of new oil and gas.”

“To fail to act, rather than merely speak out, is to tolerate a status quo that cannot be sustained,” he added in a statement.

He said he would step down when Parliament returns next week from its Christmas break.

Conservative Prime Minister Rishi Sunak has watered down some green goals that he said imposed “unacceptable costs” on ordinary people. He delayed a ban on selling new gas and diesel cars, scrapped a domestic energy-efficiency rule and greenlit hundreds of new North Sea oil and gas licenses.

Skidmore said it was “a tragedy that the U.K. has been allowed to lose its climate leadership, at a time when our businesses, industries, universities and civil society organizations are providing first-class leadership and expertise to so many across the world, inspiring change for the better.”

“I cannot vote for the bill next week,” he said. “The future will judge harshly those that do.”