Britain s Prime Minister Rishi Sunak departs 10 Downing Street, London, to attend Prime Minister s Questions at the Houses of Parliament, Wednesday June 28, 2023. AP
Zac Goldsmith, who was appointed to the House of Lords in 2019 by Johnson, said he was quitting as international environment minister and assailed Prime Minister Rishi Sunak in a scathing resignation letter.
Britain had become a leader under Johnson on climate change, environmental protections and animal welfare, Goldsmith wrote.
"But I have been horrified as, bit by bit, we have abandoned these commitments -- domestically and on the world stage," he said, accusing Sunak of "apathy".
Goldsmith noted that Sunak chose to attend media baron Rupert Murdoch's annual summer party instead of an environmental summit in Paris last week.
But the timing of the resignation -- hours before Sunak was due to hold a news conference -- raised eyebrows.
It came after the House of Commons privileges committee on Thursday identified Goldsmith as one of eight diehard Johnson supporters in parliament who had tried to undermine their "Partygate" investigation.
The committee found two weeks ago that Johnson repeatedly misled parliament in denying that lockdown-breaching parties had taken place in 10 Downing Street.
On June 9, Goldsmith had retweeted a post calling the inquiry a "witch hunt" and "kangaroo court".
"Exactly this. There was only ever going to be one outcome and the evidence was totally irrelevant to it," he wrote of the committee.
Goldsmith's identification in the follow-up report led to criticism, including from some in the ruling Conservative party, that his position as a minister was now untenable.
Quitting just ahead of Friday's news conference means Sunak is likely to be side-tracked from his preferred focus on healthcare reform, with Johnson's allies showing no sign of ending their feuding.
But the criticisms by Goldsmith over Sunak's environmental record have been made by others this week, as the prime minister battles an inflationary crisis.
The government's advisory body on tackling climate change voiced concern at the slow pace of the transition to clean energy, warning time was running out to meet its goals.