The pain for the Prince of Wales must be considerable. In the early days of his son William's courtship of Kate, the waspish Duchess of Cornwall would jokily refer to the Middleton family as "meet the Fockers", a reference to the Hollywood comedy about unconventional in-laws.
How completely that joke has now been vaporised by Carole and Michael Middleton.
As they play a major role in the upbringing of the soon-to-be 20-month-old future King George, Charles complains that he "almost never" sees his grandson.
The Mail's Shakespeare diary revealed this week that Charles is becoming increasingly perplexed about the peripheral role he plays in the young Prince's life.
Specifically, it's said that he is frustrated by the amount of time George spends with his Middleton relatives, with whom he recently holidayed in Mustique for Carole's 60th birthday.
Well, the situation could get even trickier.
For there is a "definite feeling" among friends of the Duchess of Cornwall - George's step-grandmother - that Kate's parents could be thinking of buying a place in Norfolk, where William and Kate will soon be living virtually full-time at Anmer Hall, near the Queen's Sandringham Estate.
Kate's new baby is due to arrive next month, and William will be starting his new job as a helicopter pilot with East Anglian Air Ambulance in the summer.
The Middletons have often stayed with their daughter and son-in-law at ten-bedroom Anmer - they spent Christmas there, fracturing the tradition of the normal royal get-together at Sandringham House when William and Kate were absent from the Queen's lunch.
But Carole, a miner's granddaughter raised in a council house, and founder and driving force of the family online shop Party Pieces, is a formidable, self-made woman of independence.
Watch: Prince George in Christmas photos
Getting a place of their own nearby would, of course, mean she could see lots more of Kate and her children without people thinking she was installing herself at Anmer. She is, after all, the only mother, and grandmother for George, that Kate and William have.
For Prince Charles, though, the dismay of seeing much less than he expected of his first grandson is heightened by his dreams of 'mentoring' the future king.
Just a few days before George was born, Charles was jovially asking a ladies' circle in Wales for "any hints" on being a grandfather.
"Spoil them and enjoy them - but give them back at the end of the day," he was told, amid much laughter.
On that day it was obvious to the ladies that here was a man anxious to be the attentive and loving grandfather he never had for very long himself.
Charles was only three when George VI died, and he never knew his paternal grandfather, Prince Philip's dissolute, playboy father Prince Andrew of Greece, who died in 1944.
The Queen Mother stepped into her husband's empty space and became Charles's counsellor and mentor, a vital sounding board in his life, until her death in 2002 at the age of 101.
It is not difficult to see how all of this kindled a desire to closely oversee the development of baby George, a need that is now apparently unfulfilled, despite the fact that the Prince has a special connection with his grandson, which, he believes, brings them even closer.
The truth is that he feels an empathy with his grandson because he knows that, like himself, the little chap is going to have to wait almost a lifetime before he can fulfil his destiny.
It is a unique and extraordinary situation that three generations of heir to the throne, aged 66, 32 and 20 months, are all living at the same time.
For his part, Prince Charles has always recognised that the pull on Kate by her mother would be strong. As an aide puts it: "Of course, he acknowledges that the mother-daughter thing is natural, and he's aware it's likely to be just the same when the new baby arrives."
One has to wonder, however, how different things would have been if Princess Diana were still alive to balance Carole's pull on her daughter. Camilla is little help in this respect and she has no special bond with Kate or, for that matter, much of one with William.
But is Carole Middleton really the only issue here? Friends of hers say it's unfair to put the blame on her for Charles seeing so little of his grandson.
The fact is, Kate has rushed home to her mother at every opportunity - not just when she was suffering from morning sickness - and she and William have been endlessly taking George at weekends to spend time with Carole, 60, and husband Michael, 65, at their £5 million manor house in Berkshire. Yet they have rarely, if ever, been seen at Highgrove in Gloucestershire.
"All Carole has ever wanted was to give as much guidance and help to Kate and George as any other grandmother,'" says a family friend.
"She'll be horrified to learn that William's father is apparently upset because he is not seeing enough of George. She would never want that."
When Kate was first pregnant, Carole would have been all too aware of the demands that were bound to be made on the baby prince by the palace and, it's clear, she fully accepted it.
But she would also have known that William would defend the Middletons' right to be involved - he'd repeatedly insisted this should be the case.
William's role was always going to be crucial because, until now, in-laws have traditionally found themselves frozen out in the Royal Family.
After Princess Anne married Captain Mark Phillips and gave birth to Peter and then Zara, her mother-in-law, Anne Phillips, complained she and her husband had been 'completely forgotten by Buckingham Palace'.
What even Carole Middleton didn't anticipate, though, was that William would not only make sure she had a 'say' in the early years of her first grandchild, but he would, indeed, be the driving force behind Prince George spending many days under the informal, unroyal influence of his self-made, middle-class in-laws - people whose outlook is so different from the stiffly royal approach of his father.
Of course, this was more in line with an experience and understanding of life outside palace walls to which his mother Diana had pointedly introduced him and his brother Harry at an early age.
So, how often does Charles see his grandson? The answer is not very often at all. Our understanding is that he would love to see more of George, but does not want to have to ask.
This shines an interesting light on the relationship between father and son. There are very real tensions between the two of them, and Charles often disagrees with William. But if there is an argument, friends say, Charles backs down every time.
"It's very different when William has an argument with Kate," reports a figure from their own circle. "She's eloquent and stands her ground. It's been a sharp learning curve for William, especially through the rougher passages of Kate's two pregnancies."
Handling his father, it seems, is so much easier. "Part of William is a rebel who just doesn't want to be another version of his father, or have a stuffy, traditional royal role," says a family friend. 'It's one of the reasons why he's taken the Air Ambulance job.
"I'm convinced he wants to show Charles that he can be not only a royal, but also a 'Middleton'. His message is that he's part of their family - a family that gave him a proper home life."
Could it be this that lies behind Prince Charles's complaint that he doesn't see enough of his infant grandson?
Charles is understandably happy that William has found a loving wife and a new family. But he must surely resent any suggestion that the Middletons give William what he himself hasn't been able to. After all, how could he, in the aftermath of Diana's death?
Meanwhile, Kate and William have settled into Anmer and are doing things their own way - which might not suit some traditionalists.
Just the other day, it emerged that Kate's housekeeper at Anmer, Amy Wood, had handed in her notice, together with her husband, Colin, who worked as the gardener.
Both were previously employed by the Queen at Sandringham and had agreed to switch to Anmer to work for the Duke and Duchess of Cambridge.
Now, they are believed to be going back to what the locals refer to as 'the big house'. No reason has been given for their departure from Anmer, which Carole Middleton has been visiting on a very regular basis - even though it is a three-hour-plus journey from her Berkshire home.
Carole's regular presence there only serves to highlight Charles's absence - and the growing sadness he is said to feel at the lack of regular contact with his grandson, as well as William's apparent loosening of his royal roots.
Whether or not this 21st-century, middle-class nurturing will ultimately turn out to be the correct preparation for a future king is impossible to say.
One thing seems probable. With William and Kate living in Norfolk, her parents thinking of buying a place down the road and Charles spending most of his time 170 miles away at Highgrove, it appears unlikely that the Prince of Wales will see very much more of his grandson - not to mention the new arrival next month - than he has been.
- Daily Mail