Jacob Rees-Mogg has clashed with Nadine Dorries over whether the prime minister should attend a global climate conference.
The two Tory MPs, who both returned to the back benches under Rishi Sunak, were close allies and Boris Johnson supporters.
They have previously agreed on a range of issues and stood side by side in Downing Street to endorse Liz Truss in the summer.
However, the pair had a public spat on Friday over Sunak dropping out of the Cop27 conference in Egypt.
Sunak’s predecessor Truss had been due to attend the conference next month.
However, Sunak dropped out due to “pressing domestic commitments including preparations for the autumn budget”.
Former business secretary Rees-Mogg rowed in behind Sunak, Tweeting: “The prime minister is right not to go to COP.
“The cost of living won’t be solved in Sharm El Sheikh where each hotel room for the conference is £2,000 a night.”
But Dorries hit back, telling him: “For balance, my friend…the prime minister is WRONG not to go to COP.
“Global warming is the biggest crisis facing our planet and net zero creates many 1,000s of jobs which is good for the economy.
“COP in Glasgow was most successful ever…but don’t expect media to report that.”
Sunak has been accused of “a failure of leadership” for not attending the climate summit.
Opposition parties and environmental groups said the decision showed the government was not taking the climate crisis seriously enough.