Diners left stunned as Prince William makes surprise appearance at new sustainable restaurant

Earthshot prize winner Notpla is providing some of its seaweed-based packaging to the Nursery's restaurant as an alternative to ocean-polluting plastic.

It is understood to be one of the first of many tie-ups between the ancient Duchy and the modern Earthshot, and GB News has been told "active conversations" are ongoing.

Claire Vickers, the nursery’s marketing manager, said: “William is his father’s son. He was brought up with the same values, and his interests, including unfolding The Earthshot Prize, are indicative of what he wants to do for the environment, and in that sense, we feel very much his support here.”

The King, when he was Duke of Cornwall, was heavily involved in the design plans for the new building.

Originally a slate quarry, the Duchy of Cornwall Nursery began life producing forest trees in the late 1960s and started to sell plants to the public in the 1970s.

It is now one of the largest nurseries in South West England.

On Monday, Prince William walked through the Glasshouse, part of the original nursery which is home to house plants and a special Bumblebee Garden with a patchwork of different flowers - which helps the declining bumblebee population.

Diners were shocked when the future king walked in on them enjoying afternoon tea at The Orangery.

Overlooking Restormel Castle, the restaurant uses herbs and vegetables from the nursery and the menu is inspired by local farms and the Cornish coastline.

Nine-year-olds James and Violet Scott, from Edinburgh, helped the Prince cut the official opening ribbon.

The twins were on their annual summer trip to Cornwall and were asked just moments before the event - where they chatted to Prince William about their love of the beach.

The Duchy of Cornwall is a private estate, spanning 135,000 acres and dating back to 1337, which funds the public, charitable and private activities of the Prince of Wales and his family.

Since taking over the Duchy, following Queen Elizabeth II's death in September last year, Prince William has received a private income of nearly £6million.

Prince William's Earthshot Prize was designed to find and grow solutions to repair our planet over the next year.

Winners of each category (Protect and Restore Nature, Clean Our Air, Revive Our Oceans, Build a Waste-Free World and Fix Our Climate) receive a prize of £1m to accelerate their solution.

The Prince of Wales is expected to travel to Singapore in November, which is hosting the third Earthshot Prize ceremony.