Perhaps the most iconic of the Princess’ rings was her sapphire engagement ring that she debuted in 1981.

The iconic ring now belongs to Kate, Duchess of Cambridge, the wife of Diana’s elder son, Prince William.

Lorna Haddon, head of diamonds and jewellery at Beaverbrooks, said: “Rather than a traditional diamond at its centre, Princess Diana’s iconic engagement ring holds a stunning 12-carat oval blue sapphire, which is surrounded by fourteen smaller solitaire diamonds.

“The sapphire and diamonds are set in a slim 18-carat white gold band, which accentuates the central piece and draws the eye into the precious stones.