Cartier

Prosecutor Ben Holt said the victim would usually wear a Rolex and a Cartier bracelet but when her body was found, the watch was missing.

But the rich history, combined with the Cartier name and its rare and unique design, appeared to make the piece an irresistible prize for collectors, said Ms Tonkin.

Jean Ghika, Global head of jewellery at Bonhams, said the "exceptionally rare" tiara with "impeccable provenance" dates from when Cartier London was at the "height of its creative prowess".

Fashion brand The North Face and luxury jeweller Cartier have become the latest retailers to report having customer data stolen in cyber attacks.

He also wore a gorgeous diamond necklace, its design inspired by a Cartier piece worn by an erstwhile king of the northern Indian state of Punjab.