Granny Power! Inside Carole Middleton's Unprecedented Bond with the Queen: 'There's Been No One Like Her'

There are few, if any, “commoners” who have enjoyed as close a relationship with the royal family as Princess Kate’s mom.

Carole Middleton, the daughter of a trucking company employee-turned-builder dad and a shop clerk mom, occupies an unprecedented position in raising the next generation of royals — namely, her two grandchildren: future king Prince George, 3, and his 18-month-old sister, Princess Charlotte.

Industrious, warm and energetic, former flight attendant Carole, 61 — who set up her hugely successful Party Pieces business with Michael, her husband of 36 years — always showed the way to her three children (Kate, 34, Pippa, 33, and James, 29).

“She has encouraged her children and supported them and been there for them, and set a good work ethic for them,” says Ingrid Seward, editor-in-chief of Majesty.

“I’ve never known a family drawn into the royal family like the Middletons,” a regular observer at Balmoral Castle in Scotland, where Carole was spotted in the front seat of Queen Elizabeth’s Range Rover in September, tells PEOPLE in this week’s issue. (Interestingly, Carole and her husband Michael were guests at the castle rather than at Prince Charles’s Birkhall, where they have stayed before).

While the men and and younger women (including Kate) stayed on for the shoot amid the heather on the grouse moors, Carole headed back to the castle with the Queen after lunch that day.

At Royal Ascot in June, where the Middletons have been regular guests of the Queen, an observer adds, “The Middleton parents really could be the people next door. They are lucky their daughter is going to be the future queen, but there are no delusions of grandeur. I think certainly Prince Philip appreciates that.”

There’s no doubt Prince William adores his in-laws, having first bonded with them during the years he was dating Kate. (Exhausted from training at Sandhurst Military Academy, he frequently would head to Bucklebury for a weekend respite.)

For much more on Carole Middleton, pick this week’s issue of PEOPLE, on newsstands on Wednesday.

“Because of the circumstances of William’s childhood, the Queen has made a big effort to include the Middletons much more than she would have done otherwise,” suggests Seward. “She is recognizing they have a big role in the lives of her family – and she is happy with that.”

As for Carole, who often takes George and Charlotte to the Bucklebury Farm Park, “she can afford time to devote to her grandchildren – which must be bliss for her,” says Seward. “She’ll be taking time to read to them, play with them and do all the things you want a granny to do.”

Carole, who is currently helping younger daughter Pippa plan her wedding, “is openly surprised and enjoying her situation but without any suggestion of lording it over anybody,” adds royals writer Robert Lacey, consultant to the Netflix series The Crown.

“In terms of a non-royal, young and trendy granny there’s been no one like her at all.”

He adds, “In the past, [young Princess] Elizabeth had a Scottish nanny who was the daughter of a railway signalman and actually slept in her bedroom until she was a teenager. She would teach her the habit of unwrapping your presents carefully and then ironing [the wrapping paper] and putting it back in a drawer so you could use it again.

“That sort of contact with ordinary life came through the servants in that generation — and now it’s coming through Carole.”