Addressing his sister's coffin at Princess Diana's funeral in 1997, Earl Spencer declared of his nephews Princes William and Harry: 'On behalf of your mother and sisters, I pledge that we, your blood family, will do all we can to continue the imaginative way in which you were steering these two exceptional young men so that their souls are not simply immersed by duty and tradition but can sing openly as you planned.'

Charles Spencer's powerful and inflammatory eulogy so moved the crowds gathered outside Westminster Abbey that their spontaneous applause was eventually followed by clapping inside the building.

Martin Neary, the abbey's musical director, later said of Lord Spencer's speech: 'I felt a great sympathy for what Diana had suffered but at the same time I was shocked by some of the things which were said.'

Referring to William and Harry, he added: 'The princes actually applauded at the end, although the senior members of the Royal Family did not.'

Almost three decades after the car crash in Paris that killed Diana, Lord Spencer is still close to at least one of her sons. Indeed, he enjoys warmer relations with Harry than he does with some of his own children.

William appears to have kept his distance from historian Lord Spencer, who was conspicuous by his absence at the weddings of his daughters Lady Kitty in 2021 and Lady Amelia two years later.

He has, however, become something of a father figure for Harry. This was notable on the California-based prince's recent return visit to Britain when he spent more time with his uncle than he did with his own father, King Charles.

The Duke and Duchess of Sussex and their children, Prince Archie, seven, and Princess Lilibet, five, visited the King at his Gloucestershire retreat, Highgrove, for afternoon tea. But they stayed at Althorp with Earl Spencer and his latest Countess, Cat Jarman, his fourth wife.

Earl Spencer gives a eulogy at Princess Diana's funeral on September 6, 1997 at Westminster Abbey

Earl Spencer has become something of a father figure for Harry, which was notable on the prince's recent return visit to Britain when he spent more time with his uncle than he did with his own father, King Charles

So close is Harry to his uncle that he sought advice from him about changing his family name to Spencer, as I revealed in The Mail on Sunday last year. The move would have involved ditching Mountbatten-Windsor, the name used on the passports of Archie and Lilibet. 'They had a very amicable conversation and Spencer advised him against taking such a step,' a friend of Harry said at the time.

It would have been particularly hurtful to the King, who cherishes the Mountbatten name just as his father did.

A mentor to Prince Philip, the first Earl Mountbatten of Burma, was also a strong influence on his great-nephew, the future King Charles.

Philip adopted the Mountbatten name when he became a naturalised British subject and renounced his Greek and Danish royal titles in 1947. The Queen and Philip decided in 1960 that they would like their own direct descendants to be known as Mountbatten-Windsor.

During the Sussexes' stay at Althorp, Spencer's ancestral home in Northamptonshire, they are understood to have visited the grave of Diana, who is buried on an island in an ornamental lake in the gardens. Harry had rowed Meghan in a boat to the island when they stayed at Althorp in 2022 on the 25th anniversary of his mother's death.

'At long last I was bringing the girl of my dreams home to meet Mum,' Harry wrote in his memoir, Spare, published the following year. After Harry placed flowers on her grave, he left his wife alone. 'When I came back, Meg was kneeling, eyes shut, palms against the stone.'

Last week, Meghan posted a photograph online of Harry and their children in Althorp's gardens carrying bouquets of flowers. They were believed to be making their way to lay the blooms at Diana's grave.

Meghan's decision to include the photo among a gallery of 12 snaps that she posted on Instagram, accompanied by the jaunty sounds of Cliff Richard and The Shadows' song Summer Holiday, drew criticism, with some of her followers describing it as tasteless and accusing her of 'cashing in' on Diana's grave.

Meghan posted pictures of Princess Lilibet and Prince Archie from the family's visit to Althorp

Princess Diana is buried on an island in the centre of the lake at the estate in Northamptonshire

There was, however, a little-noticed response from Lord Spencer to the criticism of Meghan and Harry.

With his agreement, his wife, Cat, posted an image of a grave herself on Instagram three days later.

It was not the resting place of Diana but of the earl's older brother John, who died shortly after birth in 1960. Charles took Cat to visit the grave at Sandringham, Norfolk, last weekend.

John is buried in the graveyard of St Mary Magdalene church, next to their grandfather. A few years ago, Charles had John's headstone restored. The church is next to Park House, where Charles, Diana and their two older sisters grew up. They moved to Althorp in the mid-1970s, when Diana was 13 or 14, after her grandfather's death and her father inheriting the earldom.

There could have been no clearer way for Earl Spencer to spell out that he approved of Meghan's social media posts from Althorp.

It's notable that the duchess did not post a single photograph of her family's visit to Highgrove. The King is unlikely to take a similarly generous view of such intimate moments being made public on an account used to publicise Meghan's commercial ventures.