The Environment Secretary defended Rishi Sunak pulling out of the Cop27 climate summit by arguing he will show “global leadership” rather than attending “just a gathering of people in Egypt”.

Therese Coffey suggested on Friday the United Nations conference in Sharm El-Sheikh is not one of the “big political summits” despite Joe Biden being expected to attend next month.

The new Prime Minister has been accused of a “massive failure of leadership” after deciding not to attend despite Liz Truss having planned to travel to represent the UK there.

Conservative former culture secretary Nadine Dorries said Mr Sunak is “wrong” not to attend the summit, saying global heating is the “biggest crisis facing our planet”.

Ministers were also being criticised for admitting they would miss their Monday deadline for publishing legally binding targets to clean up Britain’s waters and to boost the abundance of wild species under the landmark Environment Act.

Meanwhile, Mr Sunak is facing calls to go further on his windfall tax on oil and gas giants as their profits continue to soar as they benefit from high prices due to Russia’s war in Ukraine.

He is considering potentially increasing the levy or expanding it to include renewable energy generators as he seeks to plug a multibillion-pound black hole, the Daily Telegraph reported.

Ms Coffey argued Mr Sunak was “prioritising” the autumn budget which he delayed to November 17 as one of her defences of him not going to Cop27.

She insisted the “big political” iterations of the summits only take place every five years, with next month’s being more “low key”.

“The UK continues to show global leadership as opposed to just a gathering of people in Egypt,” she told LBC radio.

The UK hosted last year’s Cop26 summit in Glasgow, with then-PM Boris Johnson stressing the need to act by warning it was a “one minute to midnight moment”.

The Washington Post has reported that the US President will travel to Cop27, in a boost for the gathering and its chances of securing action over the climate crisis.

But Ms Coffey, who was demoted from deputy prime minister to the environment brief this week, told Sky News: “The big push happened last year in Glasgow.

“I am not aware of, say, President Biden or President Macron, or any of those other people will be there (in Egypt). It is quite standard practice that every five years is the big political gathering.”

Ms Coffey said she and “several senior Government ministers” will be attending but was unclear on whether the King would too now that there has been a change of leadership.

Ms Truss had told Charles, a passionate environmental campaigner, to stay away, according to the Sunday Times.

Ms Coffey told Sky News: “I think it’s up to him. I know that he takes an interest in this particular issue, but it’s up to him.”

Labour leader Sir Keir Starmer joined environmental campaigners in criticising Mr Sunak’s move.

“Britain showing up to work with world leaders is an opportunity to grasp, not an event to shun,” he said.

However, Jacob Rees-Mogg, who resigned as energy secretary as Mr Sunak took over as Prime Minister, said he was “right not to go to” Cop27.

“The cost of living won’t be solved in Sharm el Sheikh where each hotel room for the conference is £2,000 a night,” Mr Rees-Mogg tweeted.

Ms Dorries responded: “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 1000s of jobs which is good for the economy.

“COP in Glasgow was most successful ever… but don’t expect media to report that.”

Shadow climate change secretary Ed Miliband criticised the decision as a “massive failure of leadership”.

Green MP Caroline Lucas said “shame on” Mr Sunak, adding: “The first test of leadership is to turn up. The new PM’s decision not to attend Cop27 makes a mockery of any Government claims on continued climate leadership – and what a shameful way to end the UK’s Cop presidency.”

Rebecca Newsom, the head of politics at Greenpeace UK, said the move suggests Mr Sunak does not take climate change “seriously enough”.

“The UK Government is supposed to hand over the Cop presidency to their Egyptian counterparts at next month’s summit. For Rishi Sunak not to show up is like a runner failing to turn up with the baton at a crucial stage of the relay,” she added.