London-based Christie's must give details of the ownership and provenance of any artefacts it wants to bring into or out of China, the State Administration of Cultural Heritage said on its website. Antiques without papers will not be allowed to enter or leave the country.

“China has overreacted,” said James Sung, a political science professor at City University in Hong Kong. “At least 1m such items have been lost and are at different places across the world. How can it control what people do with them?”

Yesterday's decision follows protests by Beijing and art advocacy groups against the auction of the sculptures, taken from a water clock in China's Summer Palace when it was ransacked by British and French troops in 1860. A Paris court ruled on Monday that Christie's could sell the sculptures after a challenge brought by Apace, a cultural defence group.