“I can’t bear to read it,” Diana, the Princess of Wales, told me. “The headlines are bad enough.” We were in Tokyo where Diana was on tour. But the news was all about a massive brick of a biography about her estranged husband, Prince (now King) Charles. Now, more than 30 years later, the book, by Jonathan Dimbleby, seems to be doing the rounds once again.

The author was given unprecedented access and paints a vivid picture of Charles’s troubled life, from childhood to marriage breakdown. The book upset a lot of people, not just the Princess. Charles’s father, Prince Philip, later disclosed that he thought it was “bloody stupid” of his son to air his grievances in public and it had made him “bloody angry”. As for the late Queen, she had been saddened by it.

Any parent would surely be upset to read about how their son had, as a small boy, been frequently brought to tears by his father’s “bullying” attitude. Philip thought his son was “a bit of a wimp” and frequently belittled him in public, which only served to drive Charles more and more back into his shell, according to a close relation.

Philip would never have acknowledged it, but he was undoubtedly damaged by his own rootless, nomadic childhood. Exiled from their home in Greece, his parents separated after his mother was diagnosed with paranoid schizophrenia and later founded an order of nuns. He rarely saw his father, and had no real home. But, as he always said, there was no point in complaining or feeling sorry for himself – he just had to “get on with it.”

And, in a way, that spawned one of the great difficulties in his relationship with his son. As Philip himself said, he was a pragmatist and Charles was a romantic. As a consequence, he saw things in a different way, but he insisted that it didn’t mean he was “unfeeling“. And, to be fair, Charles himself later acknowledged that the advice he was given by his father was perhaps more valuable because it came from a different perspective – even if it was delivered rather brusquely.

Charles has proved himself a far more openly loving and supportive parent – though he, too, undoubtedly thinks it was “bloody stupid” of Harry to air his grievances in public with his book and TV interviews. Whereas the old Duke, in his final years, simply turned his back on the family fracas and took himself off to live in a modest farmhouse at Sandringham, Charles is trying harder. The King’s fractured relationship with his younger son is still fragile, but gradually improving. And, although there have been the usual ups and downs in his relationship with William, the two are now closer than ever.

He loves his grandchildren, sees them as often as he can and, as we witnessed, was only too happy to have little Louis clamber across and sit on his knee at the Jubilee pageant. According to Queen Camilla, he’s brilliant at reading the children stories and “doing all the voices”.

Times have changed and, as both William and Harry have shown, each generation does things in a different way. Both men are far more open about their feelings than Charles has been or Philip would ever have dreamt of.

But the late Duke of Edinburgh was proud of his children and, towards the end of the turbulent 1990s, he praised them publicly, which was all the more notable because of its rarity. At his Golden Wedding celebrations he said: “Like all families, we went through the full range of the pleasures and tribulations of bringing up children. I am, naturally, somewhat biased, but I think our children have all done rather well under very difficult and demanding circumstances and I hope I can be forgiven for feeling proud of them.”

From Philip, that was praise indeed.

Who knows what he would have thought of Harry throwing his toys out of the pram and flouncing off to California, or William determinedly putting family before duty? He’d probably have told them to shut up and just “get on with it”. Thankfully, we have moved on from those days and I believe the King is doing his best in what, ever since his marriage to Diana broke down, has been a complicated and delicate family situation.