The rulers of Bahrain were last night said to be "deeply saddened" by the theft of their wedding gift to the Prince and Princess of Wales.
British police were continuing to investigate the disappearance of the £1 million treasure, and a former butler to Princess Diana has been arrested and questioned.
Mr Harold Brown (48) is now on police bail after being questioned earlier in the week about the ornament, which vanished from the princess's apartment at Kensington Palace days after her death three years ago, it is understood. The jewel-encrusted model ship was a gift from the Emir of Bahrain when the couple married in 1981.
Last night, Bahrain's ambassador to Britain, Sheik Abdul Aziz bin Mubarak Al Khalifa, said: "We are deeply saddened to learn of this. We have full trust in the British police who are dealing with it."
The Emir of Bahrain, whose late father sent the gift to London in 1981, was being kept informed.
Today, Mr Brown, who still works for Princess Margaret, was "unavailable" for comment at his Kensington Palace home. He must return for further police questioning later this month, as must a 50-year-old man suspected of handling stolen goods, who was arrested on Wednesday.