The Beau Monde stated: “The headpiece eventually consisted of stylised diamond flowers, foliage and a heart shaped central element, all set in silver and gold.”

Maxwell Stone observed: “Based on the selling price of a similar Spencer family tiara, I’d estimate this piece to be worth around £400,000.

“With its incredible detail and the high-quality diamonds, not to mention its popularity, this is no doubt a very valuable heirloom.”

Princess Diana borrowed the Spencer tiara on several occasions, namely at a State Reception in Australia during a royal tour in 1983, and at a banquet given by the President of India in 1992.