Lord Goldsmith has quit the Government after accusing the Prime Minister Rishi Sunak of being “uninterested” in environmental issues.
The Conservative peer – a staunch ally and friend of former PM Boris Johnson – said his party was displaying “apathy in the face of the greatest challenge we face”.
Its stance made his position as climate and environment minister “untenable”.
In a stinging resignation letter sent to Mr Sunak and posted on Twitter, Lord Goldsmith said:
“Prime Minister, having been able to get so much done previously, I have struggled even to hold the line in recent months.
“The problem is not that the government is hostile to the environment, it is that you, our Prime Minister, are simply uninterested.”
Lord Goldsmith accused Mr Sunak of abandoning Tory environment pledges.
He said the “UK has visibly stepped off the world stage and withdrawn our leadership on climate and nature”.
The resignation comes a day after the peer was accused of undermining a Commons investigation into Boris Johnson.