The tiara belonged to Anne’s paternal grandmother Princess Alice of Battenberg, and it was worn by Anne’s daughter Zara Tindall to her 2011 wedding to Mike Tindall.

Alexandra Michell, Gemologist at Prestige Pawnbrokers Hatton Garden, previously said: “There is no surprise that the bandeau is of a meander design (Greek key) and has a centre laurel and honeysuckle decoration either side.

“It is studded with diamonds set in a white precious metal more likely to be platinum because of the era it was made. It is perceived to be made by Cartier in France.

“It is not known how much the tiara is worth, but I estimate it to be worth over £1million and if it is a Cartier piece, it could be as much as £2million to £4million.”