Two noble families at war, with the hapless sons caught in the crossfire. It could be straight out of a Shakespearean tragedy. Instead of the Montagues and the Capulets we have the Windsors and the Spencers locked in a bitter feud.

The latest salvos fired by Earl Spencer are brutally hostile. He portrays his ex brother-in-law, Charles, now King, as a “bellowing buffoon” who sounded “giddily elated” after the shocking death of Diana, Princess of Wales. He claims some people in the Palace were relieved, indeed pleased, that she was gone. And he depicts Prince Charles, as he was then, as a frustrated middle-aged man still waiting to reign but delighted by the fact that Diana’s death left him free to marry the woman he really loved: Camilla.

It’s all deeply personal, deeply hurtful – and completely one-sided. The King responded to the book earlier this week, saying that “the pain of fraternal grief can cloud reason, affect judgement and colour memory in ways others do not recognise”.

That doesn’t necessarily make Spencer’s claims untrue, but it cannot be the full picture. It is one man’s memory of events almost 30 years ago during a period of extreme trauma. And it certainly is not a description of the prince I came to know during those turbulent Diana years.

So where do they go from here? The King can reasonably be expected to shun all contact with Earl Spencer from now on. He might want to do the same to Diana’s two sisters, Lady Jane Fellowes and Lady Sarah McCorquodale – even though the families were friendly acquaintances from childhood. Indeed, before Diana, Charles even dated Sarah for a short time. It is, however, not unusual for an ex-husband to break off relations with his ex in-laws.

Trickier by far is how this book will affect Earl Spencer‘s relationship with the two nephews he so publicly promised to guide and protect.

We know that he has remained close to Harry, even through the past few years of turmoil. Only last month, we discovered that the Duke of Sussex and his family had stayed with uncle Charles at his Althorp estate. Did they talk about the book? It seems extraordinary if they didn’t, given Harry’s own history of writing bombshell memoirs. But all we are told is that Harry knew it was being published, but was not aware of its content.

As Harry creeps towards a tentative reconciliation with his father, things are going to get ever more awkward if the Sussexes continue to spend time at Althorp – which, given that Diana is buried there – is highly likely. It will be yet another delicate topic the King and his younger son will want to avoid.

William’s team remain resolutely silent: they will not discuss any aspect of the book or its repercussions. His focus is entirely on his job and his commitment to duty. Well, that’s the official version – but surely he must be seething that is uncle has chosen to rake up the bitterness of one of the most difficult times of his life?

I remember only too well how, just after the first anniversary of Diana‘s death, William and Harry then aged 16 and 13, issued a dignified joint statement appealing to the public and the media to let their mother finally rest in peace. They said that reminders of the tragedy brought “nothing but pain to those she left behind” and that Diana would want people to move on. Their words have clearly fallen on stony ground as far as Earl Spencer is concerned.

It is, perhaps, enlightening to recall how, shortly after Diana’s funeral, her brother was interviewed by Larry King on CNN. Still raw with the emotion of delivering his hard-hitting eulogy for his sister, it was the perfect opportunity to vent his anger about the Windsors. Instead, he said Prince Charles had not commented on the eulogy – indeed he said “nothing nasty has ever been said about it by him to me”.

So was the former prince a “bellowing buffoon” — or a man caught up in a shocking tragedy? We cannot know. But the brother who vowed that Diana‘s blood family would protect her sons has now placed them firmly in the middle of a blood feud that could last a lifetime.