An old cracked teapot with a missing lid which was bought for just £15 at an auction has been sold to the US for £460,000.
The small porcelain teapot, made in the US by John Bartlam during the 1780s, is said to be possibly the only existing item of its kind.
Estimated at £20,000, it went for 23 times that at a sale in Salisbury.
It was purchased by a London dealer on behalf of the Metropolitan Museum in New York.
Clare Durham, ceramics specialist, said it had been "very difficult to price" as there were only six other pieces of John Bartlam's porcelain known.
Described as an "important and previously unrecorded" find, Ms Durham said the teapot was a "really significant object" for the US.
"It was made in Cain Hoy, South Carolina, by John Bartlam who had come from Staffordshire in about 1760, using what we think is probably a British recipe [for porcelain]," she said.
"This is the first time they were producing porcelain in America in the 1760s, so it's kind of a birth-of-a-nation object. This is them sticking two fingers up at England, saying, 'we don't need to import your porcelain, we can make it ourselves'."
The 9cm (3in) tall vessel features two cranes beneath a tall palm tree on one side and a man on a bridge on the reverse in a bright blue pattern.
It was bought in 2016 by a collector for £15 at an auction in Lincolnshire.
Ms Durham, from Woolley and Wallis auctioneers, said the collector thought the teapot looked interesting but did not know what it was.
"It has seen better days, we haven't got the cover anymore and some decades ago the handle has been broken off into a couple of pieces and stuck back on," she said.
"It does look insignificant and it has been passed over several times in its life but luckily we've recognised it for what it is."