Left: The gold cup survived thousands of years under ground, but other finds on the site were probably lost to ploughing.

An amateur archaeologist has unearthed an immensely rare Bronze Age gold cup in a field in Kent, delighting experts at English Heritage and the British Museum.

The exquisitely embossed cup dates approximately from the time of Stonehenge, 4000 years ago, and is thought to be one of the earliest examples of gold ever found in Britain.

Some press reports have put a value of up to £250,000 on the cup.

Right: Cliff Bradshaw at the dig site.

The cup was found by metal detector enthusiast Cliff Bradshaw eighteen inches below the surface of a prehistoric barrow mound at Woodnesborough, near Sandwich.

The cup is about four and a half inches high and is beaten from a single lump of gold with great precision. It is believed to have been a ceremonial vessel.

Archaeologists have since excavated the area where the cup was found, finding fragments of bone in a grave pit.

Left: The Rillaton Cup - now on show in the British Museum.

The cup and its resting place bear a close resemblance to the Rillaton cup, found in 1837 with a skeleton, and believed to be of a similar age.

The Rillaton cup is currently on display in the British Museum's 'Prehistory: Objects of Power' exhibition.

David Miles, Chief Archaeologist at English Heritage, said: "Thanks to the team of amateurs and professionals which brought to light this outstanding and internationally important find, we have been able to undertake the vital work of excavating the barrow and placing the magnificent cup in its context."

What happens now to the cup is not clear at present. It is currently being held at the British Museum pending the outcome of a Coroner's Inquest to decide whether it is classed as treasure trove under the Treasure Act 1996. If it is, the museum will be given the opportunity to purchase the cup.