Indeed, Madeleine’s ring ranks as the most expensive of the three recent Swedish royal engagement rings.

Mr Stone added: “Bearing all this in mind, it’s likely that Princess Madeleine’s engagement ring is worth around £150,000.”

Princess Sofia’s engagement ring from Prince Carl Philip features a round diamond on a double pave band, and it was valued by Steven Stone at £10,000.

Crown Princess Victoria’s round diamond ring is an estimated two to three carats, and the jewellery experts valued it between £75,000 and £100,000.