The bracelet is stamped with “M”, suggesting that the pearls came from Mikimoto, which was quite the modern choice at the time: the Japanese jewellery house, known for its cultured pearls, had started becoming extremely popular in London in the 1900s. “Mikimoto pearls were beginning to come on the market and causing quite a sensation, because they were so much cheaper than natural ones,” says Noble.

The case for the pearls, however, came from Cartier. Done in the Art Deco style, the angular, geometric diamond clasp resembles a shield and, Noble estimates, features around one carat worth of diamonds. Engraved on the inside of the clasp is an M topped with a crown – Margaret’s royal cypher.

Small, brilliant cut diamonds also sit between the two pearl strands, a delicate detail that is often overlooked at first glance. “They’re so lovely, and really catch the light,” says Noble.

This was almost certainly a custom commissioned piece, as it’s unlikely Mikimoto and Cartier, two competing houses, would have collaborated during this time period. Noble surmises that the royal family bought the pearls, then later went to Cartier – one of the official royal jewellers – to get it cased in the au courant Art Deco style. “It would have been very stylish for the 1920s, and state of the art in terms of its fashion,” says Noble. Perfect for a young, modern princess.

After Margaret’s death in 2002, her personal jewels, including this bracelet, went up for auction. Nearly two decades later, the purchaser has decided to once again put it up for sale – and, as a result, let the world once again admire the late Princess’s priceless collection.