“No longer cut to these proportions; these rare old brilliant-cut diamonds sparkle with their own beautiful fire and brilliance.

“More of those diamonds have been additionally made into an identical diamond line bracelet which was a marriage day present from Prince Philip to his new spouse to finish the jewelry assortment.”

In terms of value, Ms Dimmick estimated a similar ring would be worth a six-figure sum, but the provenance of the Queen’s ring makes it all the more special.

She explained: “Capturing the post-World War 2 austere temper of the time, this model and proportion in 1947 was truly deemed to be pretty modest for a younger Princess.