I don't think the British have any by Cartier. I know the Queen owns the four Cartier bracelets her mother got as a gift but I'm not aware of any other major Cartier pieces in the BRF. My favorite Cartier tiara is the one worn by Princess Anastasia of Greece and Denmark. I remember reading that it had been sold later on but I can not find that info again, does anybody know. I would love for it to resurface again on some royal's head.