Rishi Sunak has been criticised for announcing plans to roll back on climate change commitments on the same day world leaders met at a UN climate summit.

The Prime Minister said in a speech from Downing Street that he believes “we risk losing the consent of the British people” for net zero policies without a change in approach and denied he was “watering down” green targets.

It comes on the same day world leaders gathered for discussions on preventing future pandemics and tackling the climate crisis at the UN General Assembly (Unga) in New York and Secretary General Antonio Guterres’ Climate Ambition Summit.

Critics have condemned the Prime Minister for his absence at the summit, warning that the UK is throwing away its reputation as a world leader on climate change.

It is shocking that the UK Government appears happy to sign up to international agreements one minute, and completely undermine them the next

Britain was also notably not among a coalition of countries, of which it is normally a leader, to sign a key statement on Wednesday pledging ambitious action on the climate crisis.

Mr Sunak’s speech also overshadowed Environment Secretary Therese Coffey’s announcement that the UK would sign the UN Ocean Treaty in New York.

Lissa Batey, head of marine conservation at The Wildlife Trusts, said: “It is shocking that the UK Government appears happy to sign up to international agreements one minute, and completely undermine them the next.

“While we welcome the signing of the UN High Seas Treaty – which is crucial to achieve the UK’s pledge to protect 30% of seas by 2030 – we are concerned that today’s climate announcements put this commitment at risk.

“Despite signing the treaty, the UK risks being left adrift if we delay or weaken ambitions to meet existing net-zero targets. The UK Government must stay on course and live up to its commitments.”

Shaun Spiers, executive director at Green Alliance, said: “Global leaders are meeting for a climate ambition summit at the United Nations today – and Rishi Sunak’s not on the list.

“Our legally binding commitment to reach net zero by 2050 ought to have earned us a place with the “early movers” showing the world how it’s done today.”

Mr Spiers said the UK has not “matched ambition with concrete action”.

“The Prime Minister claims Britain is leading the world on climate change,” he said.

“The truth is that, by sacrificing climate policies for short-term political gains, we’re throwing away hard-won progress on the climate and with it our international reputation on this issue.”

Under the Conservative government, Britain has gone from leader to laggard on climate change

Rebecca Newsom, head of politics at Greenpeace UK, said: “The UK government’s absence from Guterres’ climate summit is an embarrassment.

“The grim reality is that Britain is no longer seen as a serious player in the global race for green growth.

“Under the Conservative government, Britain has gone from leader to laggard on climate change and further planned u-turns leaked last night will only hasten our waning influence on the world stage.

“Guterres is right: the time for slogans and rhetoric is over. Real climate leaders will rise to the challenge of tackling one of the defining challenges of the 21st century.

“They will enact ambitious policies to cut emissions as quickly and fairly as possible and support the most vulnerable communities already losing lives and livelihoods to climate change. At present, Sunak is way below the bar on both.”

Meanwhile, Helen Clarkson, chief executive of Climate Group, said: “The Prime Minister should be in New York with other world leaders for Climate Week NYC and the UN’s Climate Ambition Summit, pushing for stronger action.

“He should be in New York talking to the CEOs of global businesses that are already investing heavily in going green and want to go faster.

“Instead, he’s in Westminster hatching a plan that will stifle the economy, let down voters and drive up costs for consumers in the long term.”

Mr Sunak is the first UK prime minister in a decade to skip the UN summit, blaming pressures on his diary although reports suggested he risked being barred from speaking at the UN Climate Ambition Summit since only countries that could demonstrate tangible actions on emissions would be allowed.

On Wednesday, Mr Sunak said that sticking with the status quo on climate pledges would “risk losing the consent of the British people”.

The Prime Minister said in his speech that the UK is “so far ahead of every other country in the world” on tackling climate change.

He added: “How can it be right that British citizens are now being told to sacrifice even more than others? Because the risk here for those of us who care about reaching net zero, as I do, is simple.

“If we continue down this path, we risk losing the consent of the British people.”

Mr Sunak continued: “That’s why we have to do things differently. We need sensible green leadership.

“It won’t be easy and it will require a wholly new kind of politics. A politics that is transparent and the space for a better, more honest debate about how we secure the country’s long-term interests.”