A rather extraordinary rule has been put in place for younger members of the Royal Family attending Balmoral this year - a ban on mobile phones and pictures taken at family events, Express.co.uk can reveal.

According to our extremely well-placed source, younger members of the extended family will be in attendance at Balmoral Castle next week which could prove a minefield for Palace aides.

"There has been a gentle reminder that social media posts and photos from family events are to be avoided," said the source.

"It's a private family holiday and due to extended members of the family joining this year, they are trying to keep everything as private as possible.

"There are a lot of teenagers in attendance and there would be nothing worse than seeing a photo of King Charles trying to force a potato into his mouth on social media.

"Official social media accounts are a different story because those photographs are approved by the communications team before being uploaded."

According to the source, Queen Camilla's children and grandchildren are set to join the Royal Family at Balmoral this year and will stay in the main castle which is usually used to entertain guests.

Queen Camilla is a very proud grandmother of five. Her son, Tom Parker Bowles, has Lola, 16, and Freddy, 14, and her daughter, Laura Lopes, has Eliza, 16, and 14-year-old twins, Louis and Gus.

Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6, will, of course, be in attendance, as will the Duke and Duchess of Edinburgh's children Lady Louise Windsor, 19, and James, Earl of Wessex, 16.

Other younger members of the family expected to join them include Mike and Zara Tindall's three children, daughters Mia, 10, and Lena, 6, and son Lucas, 3, although they still might head off early as Zara has entered the Wellington International Horse Trials on the last weekend in August.

Peter Phillips and his ex-wife, Autumn Kelly, are expected with their daughters Savannah, 13, and Isla, 12.

While extended members of the family and guests stay in the castle itself, senior members of the Royal Family will stay in separate more private cottages on the estate.

King Charles will stay at Birkhall with Queen Camilla while Prince William, Princess Kate and their three children will stay at a cottage known as Tam-Na-Ghar, which was gifted to William by his late great-grandmother, the Queen Mother.

"The King and Queen will remain at Birkhall and will attend dinners and events at the main castle, but it's not somewhere they stay themselves," said the source.

"The same goes for William and Kate. They will stay at Tam-Na-Ghar, but will again meet the rest of the family at the castle for special occasions."

King Charles will remain on the Balmoral estate until the beginning of September and will at some point this summer entertain new prime minister Keir Starmer, his wife Lady Victoria, and their children, as is tradition.