It was her final crusade and proved to be her lasting legacy. On the outskirts of the war-ravaged city of Huambo in central Angola, Diana, Princess of Wales had walked through a minefield that would lead some months later and after her death to a global landmine ban.

Twenty two years on, her son the Duke of Sussex made that same journey today. But he insisted the work she had begun had not yet been completed. Had his mother still been alive, he declared, “she would have seen it through.”

In a moving speech made at the exact spot where the princess was photographed in January 1997, the Duke said: “It has been quite emotional retracing my mother’s steps… to see the transformation that has taken place, from an unsafe and desolate place into a vibrant community.”

Citing statistics showing a "staggering" 60 million people around the world" still live in fear and risk of landmines", he argued: "We cannot turn our backs on them."

Visiting Huambo, he had walked the same path famously taken by the late princess in 1997, through a once dangerous area now populated with businesses and houses.