Our hereditary monarchy serves two useful functions. It is a constitutional block preventing the election of an autocratic President and it provides a focus for the nation as a talking point that keeps on giving. Everything else – charity, luxury, personality, honours, activities – whether worthy or unworthy – amount to mere window dressing.

We British got our civil war and revolutions in early. It has suited us to be governed by a parliament in the name of an impotent and generally irrelevant sovereign.

Royalists used to scare Republicans off with the thought of a President Roy Hattersley, a deputy leader of the Labour party, or, worse, President Richard Branson. After President Trump there is no need to conjure such spectres. The smile has been permanently wiped off the face of American democracy.

There is currently no serious debate about the continuance of the British monarchy provided it stays on its present course. The problem is that it can’t and won’t. Because, as an anguished Prince Philip reminded the officials planning Diana’s funeral, we are also talking about human beings.

Once again recent events have exposed the fundamental instability of the relationship between the institution of the Crown and the flesh and blood people who comprise it. Journalists, interviewers and royal watchers also need to re-assess their approach to their subjects.

Arguments over the accuracy of the depictions in The Crown television series are just the beginning. Meghan Markle chalked up a triple whammy of provocations for many in the media by winning a court judgement to protect her privacy before invading it herself with two announcements; the first about her latest pregnancy, then confirming that she and her husband are recording extended television interviews with Oprah, the American chat show host.

Meanwhile, behind the scenes displeasure from the Palace resulted in the removal from YouTube of Royal Family. The 1969 BBC/ITV documentary was made with the full cooperation of the family at the time, but Her Majesty is now said to believe that was a mistake. Much of the thrust of the film was to show the Royals were normal people just like their subjects. Perhaps too normal, by today’s standards of political correctness. In one scene the Queen jokes over tea with some senior diplomats about another visiting dignitary: “…the Home Secretary said to me “there’s a gorilla coming in” So I said: “What an extraordinary remark to make about someone – very unkind”. I stood in the middle of the room and pressed the bell and the doors opened and there was a gorilla. He had a short body and long arms – I had the most appalling trouble [not laughing].”

The most famous observation about the interaction between the monarchy and the outside world was made by an editor of The Economist during Queen Victoria’s reign. Walter Bagehot wrote “It’s mystery is its life. We must not let daylight in upon magic”. He wanted the Queen to keep out of party politics. Her heirs have followed that injunction assiduously ever since. Their instinct has also been to try to keep the shutters firmly closed on all other aspects of their lives, except those they choose to put on public display.

The problem is that this doesn’t work. People naturally want to know more about the British Head of State, especially when the taxpayer is paying. The Sovereign Grant from the government last year totalled £85.9 million.

The Royals have made efforts to satisfy public curiosity and to be seen to be doing something worthwhile. But these have only made matters worse. Those who try to set an example lay themselves open to examination; Prince Andrew wanted to boost British business and meet interesting people.

What interests the public may not always be in the public interest but even who the Royals sleep with is a legitimate, if prurient, topic since hereditary monarchy depends on the principle of the bloodline.

Then there’s celebrity culture which now overlaps with the social circle of the younger Royals.  That is all about showing off your wealth and your connections and so throws an unforgiving spotlight directly onto what is left of the magic of monarchy.

Harry began life as the spare to the heir, next in line, but was doomed to matter less and less as the Royal family grew. Decades filling the columns of the Court Circular with B grade engagements can hardly have been an enticing prospect for Harry and Meghan. They have taken the brave decision to opt out and live as celebrities rather than Royals.

This is not a soft option. Meghan needs a right to privacy because she is a celebrity, not because she was an adjunct of a constitutional monarchy. The recent New York Times documentary Framing Britney Spears shows how even the most talented women can be all but destroyed unless they can manage the pressures brought about by fame.

Meghan and Harry will have far greater control over the Oprah interview than they would on British television. That is not to denigrate Oprah’s skills. It is just that Meghan knows the rules they play by in the US, especially as in this case when interviewer and interviewee reflect their glory on each other.

The Queen doesn’t do interviews. Royal Family isn’t the only time things carefully negotiated in advance haven’t gone swimmingly. Most famously there was the mutually assured reputational destruction brought about by scoop of the century, Princess Diana’s interview with Martin Bashir. Years earlier the elderly Duke of Windsor spoke to the BBC. The uncrowned Edward VIII showed how out of touch he was, still harping on about the treatment of his wife, the former Mrs Simpson, and complaining, inaccurately it transpired, that Prince Charles was forbidden to go foxhunting. After a year of negotiations Prince Andrew agreed to an interview with Newsnight. He wanted to talk about his Pitch at the Palace charity. With great tact and fairness Emily Maitlis gave him that opportunity, but that is not what their exchange is remembered for.

When interviewees set themselves up on the lofty throne of an appointment-to-view appearance they have further to fall. I prefer the courage of spontaneity and the doorstep encounter, if you can catch them. Long ago in 1987, my camera crew and I broke Bagehot’s law and conducted what remains the only unplanned doorstep interview with the Queen – all nineteen seconds of it on Fiji’s expulsion from the Commonwealth. When I spoke to her Press Secretary Robin Janvrin afterwards, he drawled; “We knew it was going to happen, just sorry it was one of our own.” “Oh, it was you!”, the Queen was deadpan when I confessed to her at a reception some years later.

I fared less well with the Duke of Edinburgh. He and Magdi Jacoub, the heart transplant surgeon, were launching an appeal for £35 million to protect species diversity. Cameras rolling I asked what exactly they wanted the money for. “That’s a bloody stupid question,” Prince Philip replied, “it’s all in the brochure.”

Bravo, Your Royal Highness. Thanks for a truly royal demonstration of how to block and create a talking point in a crisp and classy sentence.