Treasure trove is defined in England, Wales and Northern Ireland as objects which are at least 300 years old and are made up of at least 10% gold or silver.

People who find such objects - such as metal detector enthusiasts - legally have to report them to the British Museum's Portable Antiquities Scheme (PAS) or their local coroner.

Now eBay has teamed up with the PAS to report illegal listings to a specialist team of Metropolitan Police detectives.

Roger Bland from the British Museum told the BBC:

"There are definitely some people who know perfectly well what they're doing. They're selling finds on a regular basis."

Gold and silver Roman rings have already been spotted being sold illegally on eBay.