Queen's home movies that made Wills and Harry gasp (3)

The programme concludes with a series of moving tributes to the Queen by those who know her best. William, second in line to the throne, says of his grandmother: ‘She has led where others have faltered.

‘She has just been the most incredible grandmother to me. I wish her a very, very happy 90th birthday. I hope she realises how dear and fond everyone is of her.’

His brother Harry says he would like to thank her for her lifetime of dedication. ‘Thank you, thank you so much for showing us the way and thank you for your service and dedication to the country and the Commonwealth. Thank you,’ he says.

Yacht a laugh: Prince Charles makes a splash on the slide aboard the Royal Yacht Britannia

A young Prince Charles builds himself a sand castle and smiles for the camera during some family time with his father

Fearless fun: Holiday time at Holkham, near Sandringham, in the mid-Fifties. Charles and Anne dance in the dunes and then cover themselves in the sand

As Princess Anne says today: ‘I wonder if you would get away with burying your children nowadays?

Come on brother, don’t be a wet: Andrew climbs to the top of the slide, then has to whoosh down between Charles’s legs

. . . and manages to keep a dignified pose — smiling for the camera as he slides along the deck

By the seaside: Charles and his father soak each other. He recalls: ‘It was great fun playing hide and seek in the dunes, I felt like you were never going to get out,’ to which the Queen replies: ‘In those days, you didn’t mind the prickly grass’

The Queen famously shed a tear in public when Britannia was decommissioned by Labout PM Tony Blair in 1997 — and with so many happy family holiday memories, it is easy to see why. Pictured is Prince Charles

Watching the footage, Charles reminisces at how far they used to be able to get along the deck by running a hose down the slide. ‘That slide was very popular,’ the Queen says