King Charles III abandoned plans to give a speech at the Cop27 climate change summit at the request of Liz Truss, it has been reported.
The King, who has campaigned on environmental issues for more than 50 years, was due to speak at the meeting in Egypt in November.
The Telegraph confirmed in September he would no longer travel to the summit of world leaders in Sharm el Sheikh.
It was not clear why his plans had changed, but in a report by the Sunday Times the monarch is said to have acted on the advice of the prime minister who advised him to stay away.
“It is no mystery that the King was invited to go there. He had to think very carefully about what steps to take for his first overseas tour, and he is not going to be attending Cop,” a senior royal source said.
The source said the decision was made on the Government’s advice and was “entirely in the spirit of being ever-mindful as King that he acts on government advice”.
Ms Truss raised her objections to the King’s attendance during a personal audience at Buckingham Palace last month.
Responding to the claims, Buckingham Palace confirmed to the BBC the King sought advice from Ms Truss.
It said: “With mutual friendship and respect there was agreement that the King would not attend."
A source who knows the King told the Sunday Times he would be “personally disappointed” to miss the event and was “all lined up to go”.
The King has been an outspoken supporter of environmental issues for decades. As Prince of Wales, he was often accused of meddling.
Palace sources indicated in September he would continue to champion the environment in his new role as monarch, though from a position of highlighting causes rather than campaigning for them.
Cop27 will run from Nov 6 to 18. The Terra Carta Action Forum, or Earth Charter - a 10-year “recovery plan” for the private sector - is due to take place during the summit climate talks on Nov 7 and 8. It is being hosted by the King’s Sustainable Markets Initiative, which was launched by His Majesty last January.