The items were stolen from a flat in Hong Kong belonging to Fu Chunxiao, who is a citizen of the mainland and is well known in collecting circles.

“I was dealt a huge blow and feel so sad,” he told the South China Morning Post.

“The lost items are invaluable indeed, but I cannot tell in detail what they are right now, as my mind is racing.”

“Though the value is to be ascertained, the loss is estimated at around HK$4 billion (£397 million),” an unnamed source told the paper.

One of the items stolen was an extremely rare stamp from the 1960s called The whole country is red, one of which sold for £1.5 million in 2018.