The Duke laughed when asked if he had any interest into venturing into space himself.

“I have absolutely no interest in going that high,  I’m a pilot, but I’m a helicopter pilot so I stay reasonably close to the ground,” he said.

“I’ve been up to six 65,000 feet once in a plane and that was truly terrifying. That’s high enough.

“The sky is black above you and you can see the curve of the Earth. That’s close enough to space for me ‘cause you can come back down again. It’s in the orbit so it’s okay.”

Prince George ‘annoyed’ rubbish keeps appearing after he litter picks

The Duke said Prince George, who is in Year 4 at Thomas’s Battersea prep school, could not understand why the litter he was clearing up was not going away.

He warned that it would be an “absolute disaster” if the young Prince was forced to follow in his footsteps and campaign about environmental issues in 30 years’ time, when it would be  too late.

He said: “So George at school recently has been doing litter picking, and I didn’t realise but talking to him the other day he was already showing that he was getting a bit confused and a bit sort of annoyed by the fact they went out litter picking one day and then the very next day they did the same route, same time and pretty much all the same litter they picked up back again. 

“And I think that for him he was trying to understand how and where it all came from. He couldn’t understand, he’s like, well, we cleaned this. Why has it not gone away?”

He said his elder son was “acutely aware” of the importance of the environment and had a “definite sense of realisation and understanding” about things like turning off light switches and taps.

But he said he felt “bad” and did not want to give his children the “burden of that worry” about the climate crisis.

“Charlotte is still a little bit young, she’s still not quite sure,” he said.

“And actually Louis just enjoys playing outside the whole time. He lives outside.

“But I think it is slowly dawning on them that these things matter.

“When you’re that young, you just want to have fun and enjoy it.”

The Duke expressed frustration that despite environmental campaigns by both his grandfather, the Duke of Edinburgh’s generation as well as his father’s, the planet was still in crisis.

“It shouldn’t be that there’s a third generation now coming along having to ramp it up even more,” he said.

‘We are seeing a rise in climate anxiety’

The Duke also expressed concern about the rise in climate anxiety in young people.

“We are seeing a rise in climate anxiety. You know, people, young people now, are growing up where their futures are basically threatened the whole time,” he said.

“It’s very unnerving and it’s very, you know, anxiety making.”

‘We need heroes’, says Duke on Earthshot Prize

The Duke acknowledged that trying to repair the planet was a “big challenge” he was taking on with the Earthshot Prize, which aims to find 50 solutions to the climate crisis over the next decade.

“We need heroes, we need those people who’ve really got vision, who’ve got ambition, energy, to step up, come forward and give us solutions, he said.

“The actual prize is not just about technology, it’s about thinking differently, it’s about thinking outside the box, it’s about doing stuff in a different way that makes us richer, healthier and happier in the future.”

He described seeing some of the problems with his own eyes, having been lucky enough to travel extensively.

“Every corner of the world is touched by at least one of these Earthshots,” he said.

“I’ve seen a lot of waste around the world, mountains of plastic, that’s been pretty horrible. Wildlife on screens, eating plastic bags and the jellyfish, that’s happening all the time, wherever you go. 

“I did a coral reef survey with the National Geographic in the island of Rodrigues in the Indian Ocean and that was about dynamite fishing, the impact there. Dynamite just completely eradicates the coral, everything’s gone. They’re effectively robbing themselves of future prosperity.

“And that’s slightly what we’re doing with the world. We are doing mini bombs all around the world, where that area is then completely useless for future generations.

“You’re robbing what could be a very sustainable source of income, livelihoods, jobs, health, happiness, just in one very short term hit, and that’s subsequently what we’re trying to change.”

In a lighter moment, the Duke also revealed he had never watched “It’s a Royal Knockout” the 1987 television show starring senior members of his family that has since been branded a disaster.

“I gather it didn’t go down very well,” he said.