When one of the world’s most famous environmentalists, Prince Charles, met the world’s most famous climate-crisis denier in Donald Trump, there was only ever likely to be one major topic of conversation.

Trump has revealed that Charles, Britain’s next king, spent an hour and a half trying to convince him that climate change was an existential threat to the world. But the president’s only reply appeared to be that, even if climate change is real, then it isn’t America’s fault.

Trump described the conversation to former Celebrity Apprentice contestant Piers Morgan in a stomach-churningly matey interview broadcast on day three of the president’s state visit to Britain. Morgan’s fawning climaxed with him gifting Trump with a Winston Churchill-style bowler hat, which Trump immediately proceeded to complain was too big.

The president has spent the past two days of his state visit meeting British royals and politicians—although some, such as Boris Johnson, a potential future prime minister, turned down the chance to meet him. Wednesday will see him travel to the coastal city of Portsmouth, where he will join world leaders to mark the 75th anniversary of the D-Day landings.

Despite a largely warm welcome from the royals, Trump has been met by mass public protests across the country. Thousands marched in London on Tuesday flanked by a 16-foot farting robotic Trump. Even though the protesters were just outside Downing Street while he was inside, Trump has repeatedly denied seeing them.

The president again falsely claimed there were no protests against him during a wide-ranging interview with Morgan. He also said there was “always a chance” of war against Iran, and said he “would not have minded” serving in Vietnam if it wasn’t for his great misfortune of having bone spurs.

But it was Trump’s comments on his conversation with Prince Charles that gave the greatest insight into his past few days spent in Britain. A long-established protocol dictates that foreign and domestic politicians are not supposed to disclose their discussions with members of the royal family. Not for the first time, Trump clearly couldn’t help himself.

Trump said he was due to meet Charles for 15 minutes on Monday but the meeting overran, with the prince doing “most of the talking.”

“He is really into climate change and I think that’s great,” Trump said of the prince. “What he really wants and what he really feels warmly about is the future. He wants to make sure future generations have climate that is good climate, as opposed to a disaster, and I agree.”

However, despite his warm words, it became clear that he gave no indication to Charles that he’s prepared to do anything about the climate crisis.

“I did say, ‘Well, the United States right now has among the cleanest climates there are based on all statistics,’” he told Morgan. “And it’s even getting better because I agree with that we want the best water, the cleanest water. It’s crystal clean, has to be crystal-clean clear.”

He added: “China, India, Russia, many other nations, they have not very good air, not very good water and the sense of pollution. If you go to certain cities… you can’t even breathe, and now that air is going up.”

Asked flatly by Morgan if he believed in climate change, Trump waffled on: “I believe there’s a change in weather, and I think it changes both ways. Don’t forget, it used to be called global warming. That wasn’t working. Then it was called climate change. Now it’s actually called extreme weather, because with extreme weather you can’t miss.”

One can only imagine that Prince Charles was not amused.

Trump was more coy about his discussions with the queen. He said they spoke “non-stop” for an hour and a half and that they had a “great rapport,” but added: “I promised I’ll never tell anyone about it, so I’m not going to break my promise in one day.”

That appears to be as far as his diplomacy stretched, however, as he also once again described Meghan Markle, the duchess of Sussex, as “nasty” despite previously denying he’d ever used the word “nasty” to describe her. “She was nasty about me... and that’s OK for her to be nasty. It’s not good for me to be nasty to her and I wasn’t,” he told Morgan.

Trump will leave Britain on Wednesday. Beyond upsetting some royals and getting his hands on a new hat, it’s hard to say what the trip has achieved.