The King spent Thursday carrying out state business at his beloved Highgrove retreat.

The 18th century countryside estate near Tetbury, Gloucestershire, serves as the private home of Charles and his wife Camilla, now the Queen Consort, and is something of a sanctuary for the King.

A spokesman for Charles said he was busy with state business, including phone calls with governors-general and contact with heads of state.

Charles, a passionate gardener, has spent more than 40 years devoting his energy into transforming the gardens around the house, which are now visited by thousands of people every year.

Archive photographs from Clarence House show Charles, aged in his 30s, with secateurs in one hand and a cutting of a shrub in the other, dressed casually in an opened-necked checked shirt and belted chinos, as he walks through the meadow in front of Highgrove House.

The organic gardens opened annually to the public in 1994 and in 2019 Clarence House said tours, along with events, retail and catering at Highgrove have raised more than £7 million for charity over the past quarter of a century.

Highgrove was acquired by Charles in 1980, when it had only a kitchen garden, an overgrown copse, some pastureland and a few hollow oaks.

The gardens are now peppered with personal touches and the mark of the family – from a tree planted by Prince George to the treehouse built for a young Prince William.

George’s Balsam Poplar tree stands close to the main Highgrove house, with a plaque bearing the words: “This tree was planted by Prince George of Cambridge on 23rd March 2015.”

He was just under two when he joined his grandfather to plant the lasting memory of time spent in the gardens together.

The treehouse – named Hollyrood House, given to William in the late 80s and used by him and his brother Harry when Highgrove was their childhood home – was rethatched in 2018, restored for future generations.

Seventieth birthday gifts to Charles are among the more recent additions to the gardens.

A wooden beehive was a present from Fortnum & Mason, while a slate bust of Charles and Camilla, depicting them smiling with their heads together, stands in the Winterbourne Garden – a gift from the prince’s friend, businessman Sir Don Gosling.

Charles took on a 70th birthday project, installing a new Azalea Walk, lined with giant terracotta pots filled with azaleas.

The King is also a fan of scented flowers, in particular a yellow climbing rose.

One of his favourite roses is Jude the Obscure, a citrus-scented yellow rose which decorates the Shand Gate – the entrance to the garden which was renamed in honour of Camilla’s late brother Mark Shand.

Fruit and vegetables from the Kitchen Garden are used for Charles and Camilla’s table, while cut flowers in the house tend to come from the garden.

Topiary includes yew hedges in the shape of a squirrel, a boar, a snail and a toad, while modern additions to the gardens include a Bluetooth-controlled irrigation system.

Charles has also ensured rare trees and plants have been grown for future generations to enjoy, and heritage seeds have been planted to make sure the varieties continue to flourish.

A Wildflower Meadow stretches out across four acres in front of the house.

Charles has said of the gardens: “One of my greatest joys is to see the pleasure that the garden can bring to many of the visitors and that everybody seems to find some part of it that is special to them.”

Each year, the estate – which also has an Orchard Tea Room – typically welcomes around 40,000 visitors.