King Charles makes changes to favourite royal home for George, Charlotte and Louis

A childhood inside the Royal Family is undoubtedly a pretty unique experience - and as a thoughtful grandfather, King Charles has gone out of his way to make it even more special.

In a new documentary about one of Charles's all-time favourite royal residences - Birkhall - experts have revealed that he has gone the extra mile to ensure his grandchildren enjoy coming to visit. The documentary, called Birkhall: The King’s Secret Sanctuary, explores just why this relatively modest lodge house located close to the imposing Balmoral Estate holds such a special place in Charles's heart.

Whenever Charles is seen with his grandchildren, Prince George, 12, Princess Charlotte, 10, and Prince Louis, six, it's clear that he shares a special bond with the Wales children - who all supported him at his coronation in 2023, with George even taking on a prestigious role as page of honour.

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The monarch is also said to be close with his step-grandchildren, who are said to "adore him". Tom Parker Bowles, Camilla's son, has said they have nicknamed the King 'Uppa' and Camilla has revealed that they love when he tells them stories, because he really commits to doing the voices for each character.

Birkhall is, according to the experts, the real "marital home" of Charles and Camilla - it's even where Charles popped the question and asked his long-time love to become his wife. So it's no surprise that the couple worked to make it family-friendly, so their whole brood of grandchildren on both sides have a great time playing when they visit.

There are three ways in particular that Charles has ensured the children will have the same good memories of Birkhall as he does, the experts revealed in the documentary. Firstly, a Wendy House that the late Queen - then-Princess Elizabeth - and her sister Princess Margaret played in as little girls still stands in the ground of Birkhall, and Charles has ensured it is still in good enough condition for the little ones in this generation to enjoy - nearly a century later.

Jennie Bond, former royal correspondent for the BBC, explains, "It's really cute, it's so beautiful, it's got this thatched roof, but it's thatched with heather, and the walls are covered in bark, it looks like there should be a fairy in there or a gnome living at the end of your garden.

Expert Mark Lane explained, "Just to think that Princess Elizabeth and Princess Margaret used to play there, have a wonderful time there, and now all the rest of the grandchildren can continue to play in the garden I think is a wonderful thing."

He also noted that Charles has "always said that" he wants to keep "family tradition going through" - and it definitely seems to be working.

But Charles hasn't stopped there, Mark reveals, there is a seriously exciting other feature he has designed for the youngsters, "So there is a bouncing bridge, and he [Charles] says 'You've just got to bounce on this bridge because it's so much fun'".

Finally, the expert revealed, "There are small strawberries that kids can pick at the side of pathways, and he just always hopes that when Prince George has grown up, he too will love the trees and love Birkhall.

Charles first spent time at Birkhall when he was, himself, just a little boy - when it belonged to his "beloved" grandmother, the Queen Mother. She took over the property in the 1950s, and she and Charles were always very close - with one royal author even saying that he perhaps saw her more like a mother figure than the late Queen herself, due to his mother's busy schedule as monarch often meaning she was away from him for long periods of time when he was a young boy.

The experts explained that during his unhappy school years at Gordonstoun in Northern Scotland, he travelled as often as he could to see his grandmother at Birkhall - and even now they claim it is one of the only places Charles feels real "freedom".

After the Queen Mother died in 2002, the property passed to Charles, and he and Camilla carefully renovated it, making sure to put their own stamp on the place, whilst keeping a sense of his grandmother present too, with Charles left utterly "devastated" by her death.

This includes keeping some of her prized decorations in place, but also another heartbreaking tribute - the Queen Mother's coats still hang by the door, as if she would be back at any moment.

Birkhall: The King’s Secret Sanctuary, airs Saturday 21 June at 7.30 pm on Channel 5.