“Not only is it an incredibly sentimental choice for this reason, but it’s also an appropriate one as white jewels such as pearl and diamond pieces are often worn for mourning – a tradition that dates back to Queen Victoria.

“The brooch features a trio of pearls placed in the centre of a pave-set leaf and is quite a substantial piece. I’d estimate its value to be approximately £60,000.”

Kate additionally wore the Duchess of Cambridge brooch in a royal portrait with Prince William in 2022, just before she became the Princess of Wales.

Maxwell added: “Not only is the late Queen’s Duchess of Cambridge brooch one of the most valuable brooches in her collection, but it’s also one of the most historic as it originally belonged to Princess Augusta of Hesse-Kassel, the wife of Prince Adolphus, who was the Duke of Cambridge in the 1800s.