Guan added that the repatriation also sets a good example as this year marks the 50th anniversary of the UNESCO Convention on the Means of Prohibiting and Preventing the Illicit Import, Export and Transfer of Ownership of Cultural Property, commonly known as UNESCO Convention 1970. China joined the convention in 1989.

Guan said one reason the repatriation of the 68 relics was difficult back in the 1990s is the absence of a shared legal basis for the process before the UK joined the convention in 2002.

"Repatriation of lost relics not only involves complex legal issues," he said. "It is also connected with people's collective emotions and international relations. As an issue of shared difficulty for the world, the solution requires consistent efforts over generations."

But he added that international law has undergone a historic change in the past 20 years and returning lost relics to their origin is becoming a worldwide consensus.

"So this achievement jointly reached by China and the UK has global significance in providing support for similar cases," he said.