The seller of a Qing vase auctioned for £53m last year has flown to China in a final attempt to persuade the bidder to pay up.
The sale of the 1740 vase by retired solicitor Anthony Johnson and his mother, Gene, smashed its original estimate of £800,000. But five months later, the "buyer" has not paid anything to Mr Johnson, 54, or his 85-year-old mother, who live on the Isle of Wight.
Mr Johnson and auctioneer Peter Bainbridge, who sold the vase, reportedly flew to Shanghai last week to meet the buyer, said to be a "wealthy industrialist" with links to China's government.
A source said: "Mr Bainbridge and Mr Johnson want to return considerably wealthier next week. If they leave without the cash, the vase may go to the underbidder or be put back under the hammer."
It has been reported that the Johnsons may be at the centre of an elaborate Chinese government protest against the sale of treasures looted from the country, where agents are sent to bid for items – and then fail to pay up. Mr Bainbridge has denied that the auction was sabotaged.
In 2002 the Chinese government set up the Lost Cultural Relics Recovery Program to reclaim artefacts. In some cases, it buys back antiques.
But in 2009, when Christie's in Paris sold bronze animal heads looted from the Summer Palace in 1860, a Chinese buyer – an adviser to a government heritage organisation – made a winning bid of £13m but said he would not pay as "an act of patriotism".
An antiques source said payment for the Qing vase should have been made by 9 February.
Mr Johnson and his mother inherited the 16in porcelain vase from her sister, Patricia Newman, in January 2010. It had belonged to Ms Newman's husband, Bill.