Prince William left members of the public stunned as he served up "Earthshot burgers" from a truck in south-east London

He was joined by the crew of the YouTube channel Sorted Food and was checking in on last year's winners.

William was joined by Ben Ebbrell, the founder and chef of Sorted Food, and Kush Bhasin, the head of food, to try out three eco-friendly Earthshot winners' inventions.

The future king said: "I can't vouch for the taste and the quality - that's up to Kush and Ebbers - they designed the menu, so I'm rolling with it."

He also tested out the gadgets in the mini kitchen and Jamie Spafford, co-founder of Sorted Food, joked that the 41-year-old royal was from "Royal Mail" as he arrived with the packages with the ingredients inside.

Indian start-up Kheyti designed the "greenhouse in a box" for farmers to shelter their crops from bad weather and to deter pests.

What's more, the burgers were cooked in an eco-friendly portable stove from Mukuru Clean Stoves from Kenya, which uses processed biomass for fuel so there's less air pollution.

And the takeout packaging is made from biodegradable boxes made from seaweed and plant extracts to reduce the use of plastic.

Members of the public who tucked into the tasty treat dubbed them "the best burger we've ever had".

William had joked that he "had hair" when he first started the Earthshot Prize in 2020, before going on to explain the initiative.

He said: "It's designed as an environmental prize tackling the world's greatest environmental problems."

The prince continued: "We liked the idea that this is a big deal, this is like something we really need to aim for, but it's about saving the planet, not taking us to the moon.

"And there's many people out there who want us to move to the next planet already and I'm like, hang on, let's not give up on this planet yet."

Each year, five winners receive £1 million to take their ideas to the next level.

Sorted Food teamed up with Earthshot Prize through its YouTube partnership to encourage people to make changes to improve their carbon footprint.