Royal biographer Tina Brown also wrote in her book ‘The Palace Papers’ that Prince William once warned guests at a breakfast buffet to stay away from his father’s linseed breakfast. Then Prince William told guest Stephen Fry that King Charles’s breakfast choice of linseed was like “bird food”.

“At breakfast at Highgrove, Fry was inspecting a buffet when he lifted a tureen that offered Charles’s preferred heap of Linseed. Prince William said ‘Oh no, don’t go near the bird table, Stephen, that’s only for Pa’”, Tina Brown wrote in the book.

Leading nutritionist Signe Svanfeldt talked about King Charles’ diet. “Linseed can aid digestion and is high in protein, fibre and essential fatty acids (omega-3). For breakfast, King Charles is known to enjoy homemade bread, fresh fruit and fruit juices – which have many nutritional benefits. Home-made bread typically contains more nutrient-rich flours such as rye and spelt plus fibre- and protein-rich seeds, including psyllium or linseed. Fresh fruit and fruit juices will help to boost the King’s vitamin, mineral and fibre intake,” Signe Svanfeldt explained.

King Charles’ former press secretary Julian Payne said that the monarch does not eat lunch at all.

“The King doesn’t eat lunch; so, an early lesson I learnt when out on the road with him was to have a big breakfast or bring a few snack bars with you to keep you going. The working day is pretty relentless. Beginning with the radio news headlines and a breakfast of seasonal fruit salad and seeds with tea,” Julian Payne said.