A rare 200-year-old Chinese flask found in Shirenewton is set to go under the hammer on 7th November, valued between £500,000 and £800,000.

The Chinese Dragon moonflask is one of only five of its kind, and its location has been unknown for the past eighty years.

The piece was made for an Imperial palace in China between 1736 and 1795. It was brought to the UK more than 100-years-ago by wealthy Shirenewton tea merchant Captain Charles Oswald Liddell.

Mr Liddell worked in China between 1877 and 1913, and brought the flask with him when he moved to Shirenewton Hall, previously Shirenewton Court. He then went on to become Sherrif of Monmouthshire in 1918.

The rare piece will be auctioned at the Fine Chinese Art Sale at Bonhams in London. Colin Sheaf, chairman of Bonhams said: "I'm thrilled to be auctioning this Imperial Dragon moonflask, because fewer than five seem to be recorded and this beautiful example has been 'lost' for eighty years.

"The shape copies the metal water-bottles carried by camel riders along the Silk Road five hundred years ago. This explains the apparently functionless small handles surviving on the neck.

"The design of these majestic snarling dragons, both with the Imperial identifier of five great claws, is very rare.

"The way it is painted, too, is rare and expensive originally. The red and blue colours, ground-up cobalt and copper oxide, are painted underneath the clear glaze and then after it has been fired for the first time, much of the vase has been decorated in translucent turquoise and lime-green enamel on top of the glaze and fired a second time to achieve this vibrant contrast of colours.

"There must have been hundreds of unsuccessful efforts. For the colours are really difficult to fire in the kiln.

"Happily, this one passed quality control and should now make a record price at Bonhams."

Captain Liddell and wife, Elizabeth, had four sons: Percy, Kenneth, Norman and Charles junior – who were all born in China. The Captain died in 1941.