With regards to the value of the sparkler, some experts have estimated the ring could be worth a six-figure sum.

Alexandra Michell, Gemologist at Prestige Pawnbrokers of Channel 4’s Posh Pawn, told Express.co.uk: “An Art Deco five-carat emerald cut diamond ring, flanked with stepped baguettes mounted in platinum.

“Linear patterns and monochromatic colours are enhanced by a very clear centre stone, which will also give off flashes of multicolour; this is an elegant and timeless piece.

“This 1930s ring had belonged to the Queen Mother, and is believed to have been left to her by Mrs Greville when she died. It has been valued in the past for £100,000.”