POWERFUL. HONEST. RAW. BUT WILL PRINCES REGRET THEIR TESTIMONY OF GRIEF?

Powerful. Honest. Raw. But in honouring their mother, will Princes rue the day they shared their...

IT IS 22 years since Diana, Princess of Wales uttered one of the most famous quotes in Royal history. Speaking on a devastating Panorama documentary about her husband’s relationship with the Duchess of Cornwall, she said: ‘There were three of us in this marriage, so it was a bit crowded.’

It’s a soundbite as cruelly compelling today as it was at the time when it fired the gun on Charles and Diana’s bitter divorce proceedings.

What is less well remembered is that the Princess came to rue her candour and its consequences for the wider Royal Family and, of course, her beloved sons William and Harry. While I understand their need, as adults, to honour their mother’s memory on the 20th anniversary of her death, I worry that they have not learned the lessons of the past.

They too have been honest, putting their raw emotions and private beliefs in the public spotlight. Like their mother’s confession of her own adultery and her revelations about her damaged marriage, these words can never be erased.

The ITV documentary which they have championed and contributed to, Diana: Our Mother, Her Life And Legacy is indubitably brilliant viewing.

The two Princes, now 35 and 32, offer what amounts to a testimony of grief. Their appearance, occasionally close to tears, on camera was clearly a challenge. They have never spoken so openly about their mother before and they say, they will never do so again.

The question is: should they have done it at all?

For this is about more than Diana and her legacy.

It is about the future course of the Monarchy, as understood by the brothers who will one day be at its helm.

It’s an institution that has survived much over the last millennium but historically it has weathered its storms in silence. Speaking so powerfully about grief and loss – no matter how authentic and how moving – goes against the grain.

Indeed, there will be some who accuse the two Princes of being a little self-indulgent; they will have their critics both within and without palace walls. Comparisons will be made to Her Majesty the Queen who, aged 91, and the longest serving Monarch in British history, has never given an interview and never will.

Her reign has seen much modernising but when it comes to personal matters she has cleaved to the advice given to her great-great-grandmother Queen Victoria by essayist Walter Bagehot who wrote of the Monarchy: ‘Its mystery is its life. We must not let in daylight upon magic.

‘We must not bring the Queen into the combat of politics, or she will cease to be reverenced by all combatants.’

What the Princes are handling here are the politics of the heart and how much of them should be on display. They are surely wishing to harness public opinion, to share common ground with their subjects for the good of all. But what if their subjects come to the conclusion that the Wales brothers really are just like them?

Where then is the power vested in the Monarchy by state and church which requires them to be the leaders of their people? It is greatly taxing the Queen. Her private secretary, Christopher Geidt, has already made it known to the Royal households that however commendable Kate, William and Harry’s Heads Together mental health campaign is, their level of soul-baring and its projection in the media was not necessarily what Buckingham Palace wanted.

There have also been stern words spoken about how the campaign, with its easy access to the young Royals through radio broadcasts, podcasts and photo calls, has overshadowed the work (dutiful, occasionally dull but hugely necessary heavy lifting done by less glamorous members of the Firm) of others.

SO FAR William and Harry have flagrantly ignored warnings from courtiers. This documentary is where the conflict between the old and new reaches its zenith. They would not be doing it unless they believed it was right for them and for the future of their family. The Queen has said that she has to be seen to be believed but her grandsons clearly feel that, in this era of rolling 24 hour news and social media, they have to be heard, too. Diana is after all their domain, and by making this film they reclaim her memory and gain some kind of authority over her ghost.

And, setting aside the issue over the rightness of making it, this is a magnificent piece of television.

As a Fleet Street journalist who has chronicled the Royal story since 1990, I had a ringside seat as the fairytale marriage of Charles and Diana erupted into the War of the Waleses. I remember all too clearly how farce and drama turned to tragedy and Diana died in a Paris underpass in 1997.

It has taken 20 years for her sons to tell their own story of those years, the distress, the divorce, their longing to spend more time with both of their parents and above all the devastation of her death and the hollowness which followed.

It is perhaps only now that William has made a happy marriage and become a father himself that he, the most buttoned-up of the brothers, has been able to articulate all this. As for Harry, while he doesn’t yet enjoy the same stability as William, there is evidence aplenty of his maturity and self knowledge. They have grown into the men Diana wanted them to be, and this documentary is part of that playbook.

It is meant to be humble, honest and loving, a monument to their mother as solid as anything which could have been cast in bronze and mounted on a plinth in Kensington Gardens.

Like her, they view being relatable as a way of future proofing an institution whose popularity was shrivelling because as of its remoteness.

Diana, with her advocacy of tough and unfashionable causes from Aids to landmines, was far, far more than a ribboncutting Royal.

She also, for right or for wrong, made herself relatable. Her sons want the same.

This is part of that legacy. It’s admirable. It makes for landmark television.

It’ll take another 20 years before we know if it was the right decision and if they, like their mother before them, will come to regret throwing open the curtains and letting in the brightest of daylight.