The sapphire, originating from Sri Lanka, is a deep, royal blue, of AAAA quality, “making it among the most valuable of its kind”.

Steven Stone commented: “Both rings definitely have a vintage feel, however, Pippa’s design is slightly more modern than Kate’s, which was originally purchased by Prince Charles in 1981.

“Kate’s ring is also much more controversial. At the time of Prince Charles’s proposal to Diana, the ring received a lot of backlash, often being referred to as the ‘commoner’s ring’, because while being a creation from former Crown jeweller Garrard it was not a unique design.

“It was also available to the general public, providing they had £28,500 to spend, which was the estimated price of the ring at the time.