Rishi Sunak has told a Cop27 reception hosted by the King that the world will experience “more human suffering” if we continue to allow “climate change to ravage our planet”.

The Prime Minister is attending Cop27, the UN climate conference, in Egypt next week after a U-turn but Charles will miss the gathering of world leaders, business figures and environmentalists.

The King has long campaigned on environmental issues and last autumn he told the Cop26 talks in Glasgow that the world has had enough of talking and commitments needed to be put into practice.

But the “soft power” diplomacy of the monarchy will be absent from the international gathering at Egypt’s Red Sea resort of Sharm El-Sheikh.

During Liz Truss’s brief premiership, a “unanimous agreement” was reached that the King should not attend Cop27 after advice was sought by his office from the Government.

Speaking at a reception staged in the Buckingham Palace ballroom on Friday, Mr Sunak said: “As recent events have shown, delivering on the promise of Glasgow is more important than ever.

“More important because as we have seen so starkly with the war in Ukraine, it is vital to invest in secure, renewable sources of energy and sustainable food production.

“More important because every moment we allow climate change to ravage our planet we will see more human suffering like the devastating floods in Pakistan.

“And more important because if we do not act today, we will risk leaving an ever more desperate inheritance for our children.”

Among the guests at the palace from the world of finance, technology, transport and agribusiness were a number of Government figures, including Environment Secretary Therese Coffey, Business Secretary Grant Shapps, International Trade Secretary Kemi Badenoch and Cop26 President Alok Sharma.

Labour leader Sir Keir Starmer was also in attendance, alongside Bank of England Governor Andrew Bailey, while foreign leaders included Mia Mottley, the prime minister of Barbados, and Saudi Arabia’s Ambassador Prince Khalid bin Bandar Al Saud.

Mr Sharma, who will be handing over the UK’s presidency to Egypt at the summit, has reportedly said he would “welcome” Charles’s presence at Cop27, while fellow guest John Kerry, America’s special envoy on climate change, echoed his words telling Sky News recently it would be “very powerful” if the King was in Egypt.

Fashion designer and sustainability activist Stella McCartney was asked at the reception if it would be a “good idea” for the King to attend Cop27, and she replied: “I think it’s good to have him everywhere talking on this subject matter but I don’t think it’s realistic to do so.”

McCartney, who joked with Charles when she first met him, went on to say: “That’s really the beauty of today and the work that King Charles has been doing, he is truly getting the world leaders in business and the world leaders in politics into the same room.

“They’re all here for one reason – people are facing problems, we need solutions and we all have to work together.”

In his speech the Prime Minister also paid tribute to the King for “helping to find practical solutions to climate change and biodiversity loss for more than 50 years, long before Cop1 let alone Cop27.”

He added: “The reduction in global emissions pledged during our presidency is now equivalent to more than six times the annual emissions of the entire global aviation industry.”

Addressing the guests Mr Sunak said perhaps the greatest breakthrough of the UK’s presidency of Cop26 was an idea suggested by Charles – bringing together leading investors and businesses at Glasgow to direct the world’s wealth at protecting the climate.

He said: “As a result of what many of you here are doing today, we’re turning the fight against climate change into a fantastic source of new green jobs and growth.”

Charles ended the day by planting a lime tree in Buckingham Palace’s garden as part of the Queen’s Green Canopy project – thought to be the first time he has carried out a tree-planting ceremony as monarch.

The initiative has planted more than a million trees across the UK to honour and celebrate the Queen’s 70 years of service to the nation.