Illegal detectorists targeting Gloucestershire farmland
So-called "nighthawkers" who hunt for buried ancient artefacts are targeting farmland in Gloucestershire.
The illegal practice involves people using metal detectors at night to hunt for valuable objects.
Gloucestershire Police said it contravenes the Countryside and Rights of Way Act 2000 and is rife during late summer after fields are ploughed.
Farmer Graham Nichols, from Kingscote, said the people involved know what they are doing is illegal.
Mr Nichols claims there are 150 acres of Roman settlements beneath his farmland.
He said: "It's where people come with metal detectors to try and find Roman remains. The problem is all this land is scheduled so it's an illegal activity."
"They know what they're doing is illegal as they are coming out at night when it's dark," Mr Nichols added.
"This is history, and once they've taken that history away it can never be put back there, and this is the future for generations to come."
Gloucestershire Police Sgt Garrett Gloyne said: "It happens at a particular time of year after farmers have harvested crops and fields have been ploughed."
He warned if someone is found using a metal detector on a scheduled ancient monument they could be arrested, and also urged the public to notify the force of any suspicious activity.
Historic England's Mark Harrison said: "Illegal metal detecting is not a victimless crime. We may never see or fully understand the objects taken or damaged because they have been removed from their original sites with no care or record as to their history or context."
He added: "Historic England will continue to work with the police, Crown Prosecution Service and the metal detecting community to identify the small criminal minority who are intent on causing loss and damage to our shared cultural heritage and to bring them to justice."