You know a line has been crossed when not just Buckingham Palace issues a complaint, but Clarence House and Kensington Palace also. In response to the BBC documentary The Princes and the Press, presented by Amol Rajan, the famously uncomplaining royals issued a joint statement condemning its use of “overblown and unfounded claims from unnamed sources that are presented as facts”.

Watching the first episode, the absence of insiders prepared to go on the record as they fed titbits about William and Harry and their wives to the press was painfully apparent. The occasional “anonymous” quote is acceptable, when bolstered by solid fact, but there were so many innuendoes and opinions rather than matters of substance that the programme felt like a doughnut: sugary, greasy, unhealthy, with a big fat hole at its heart.

I had that queasy feeling of bitching about someone behind their back. Journalists’ glee as they recounted their front-page scoops was revolting. They almost salivated with excitement at discovering intimate details about the private lives of the royal family ahead of the rest of the press corps.

Even more unsettling were the confessions of a private investigator, hired to find the medical records of Prince Harry’s then girlfriend, Chelsy Davy. The hope was to discover a history of abortion or sexually transmitted diseases. We also were reminded about Kate and William’s phones being incessantly tapped when they were dating, and saw footage of paparazzi shamefully crowding the royals and their friends, like hyenas circling their prey. Has nobody heard of Diana?

Meanwhile, Rajan left the worst offenders lightly grilled rather than roasted. As a former editor of the Independent (which in its heyday I recall steered clear of royal stories), and now the BBC’s media editor, he understands better than most how the press pack works.

Pack is certainly the appropriate term, because it is ferocious and frequently feral. One member of the tabloid press talked disparagingly of the palace being “a nest of vipers”, yet the reporters that follow Harry or Megan’s every step are hardly an advert for love and harmony. Palace watchers cite “public interest” as their motivation for grubbing around for scandal, but we all know that the truth is simpler than that: royal revelations sell papers. Pitting the princes against each other was a fiendish tactic for ensuring ceaseless stories, even if their origins were based on grievances and gossip.

If nothing else – and there was little else – The Princes and the Press made plain the toxic and abusive relationship between the younger members of the House of Windsor and the media that stalks them. They have been obliged to make an almost Faustian pact: offering a degree of access into their lives in return for coverage of their official duties. But when they don’t offer enough for an editor’s liking, or readers grow bored with them, overnight they become the target of spite.

Not since the hounding of Princess Diana has the full horror of the way the royals are treated been so apparent as in this documentary. There is horror in the way they are exploited, and in how they are manipulated. You can argue over the wisdom of some of their actions, but would it make any great difference to the outcome? Pirhana fish must eat, whatever is on the menu. Even if they were paragons of virtue and sagacity, they would be mocked for being dull and worthy. And, when they show alarming signs of being normal and human, by making gaffes or misjudgements, they are never allowed to forget them.

Responding this week to a book that alleges Charles questioned what colour of complexion Harry and Megan’s future children might have, a representative of the Prince of Wales dismissed it as “fiction”. This, surely, is how they must view much of what is written about them.

How does it feel to wake up and see headlines about your private life, and that of your loved ones, whether true or invented? Read further, and there’ll be reams of columns, airing subjective and prejudiced views. I am fully aware that in writing this, I am adding to the cairn. Yet at some point each of us has to ask why we are doing it, and where we should draw the line. I think I’ve probably reached mine.

None of us has a clue what the Windsors are really thinking, behind their well-schooled expressions. When Harry is said to be looking daggers at photographers, might he simply be bored out of his mind? And when any of us, press or public, offers our interpretation of events, it is based on impressions, not genuine insight.

The same is true of those experts in body language, who are asked to analyse the dynamic between family members. Their conclusions are merely a guess, not a signed affidavit by those concerned. In some respects they are not so far removed from entrail-readers hired by kings of old, who stirred a bird’s intestines in order to peer into the future.

News reporting on the activities of the royals who are paid by the public purse is necessary and at times – such as the allegations against Prince Andrew – important. Most of the rest is scuttlebutt. It is also immensely cruel. Compared with William and Harry, the pandas at Edinburgh Zoo enjoy more privacy. Why can’t we leave them in peace to enjoy lives that, while wealthy, are utterly unenviable?

George Clooney was astounded some years ago when, after he was seriously injured in a motorbike crash, onlookers ran around taking photos. As he lay there wondering if he was about to die, he realised “that you really are here just for their entertainment.” The same is true for the princes and their families. Journalists and commentators can dress it up as an intellectual exercise, or go straight for the jugular. Either way, dissecting the royals is inhumane. Like all blood sports.

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