The public body responsible for looking after some of England’s most historic places has issued a stern warning to people who indulge the art of stone stacking in protected spots.
Historic England said that in some circumstances people who balance or stack stones may be breaking the law and could even face jail.
Stacking or balancing stones is a pleasing pastime for some lovers of the outdoors and a precarious natural sculpture is a familiar sight on mountain, riverside and beach.
But Historic England said stone stackers should not tamper with spots classified as ancient monuments.
The warning followed concern that stone stacking was putting a neolithic site called Stowe’s Pound on Stowe’s Hill in Cornwall at risk.
A group called Caradon Archaeology posted images of “fairy castles” – stone stacks – on its Facebook page and called for the registration plates of anyone seen piling stones to be taken and reported.
The post said: “Stowe’s Hill is a 6,000-year-old settlement, built by our neolithic forebears. It is a protected scheduled monument.
“This practice is not only vandalism, it is illegal and carries with it a possible prison sentence. If anyone sees anyone attempting to move stones please warn them of this and message us. Or try and get their registration number and message it to us.”
Stuart Dow, 67, from Launceston, Cornwall, one of those concerned about Stowe’s Hill, said he liked stone stacks in the right place. “But a neolithic site is not the right place. It’s disrespectful.”
Historic England said: “Monuments scheduled under the ancient monuments and archaeological areas act 1979 are of national importance.
“Permission is needed from Historic England if anybody wishes to make any changes to these protected monuments, including the moving of objects that belong to them.
“Any action that is potentially damaging to a scheduled monument will be investigated by Historic England in partnership with the local police and local landowner.”
The organisation added: “Together we can use a range of interventions to deal with an incident in order to protect England’s historic environment.
“These interventions include restorative resolution, formal warnings and in some cases, prosecution. In some instances offences are imprisonable.”
Stowe’s Pound on Bodmin Moor is one of a number of tor enclosures found in Cornwall where prominent hilltops were enclosed with substantial banks and ditches.
It is believed to have been an important site for gathering and the exchange of goods and ideas at the time that a lifestyle based on farming was replacing one of hunting and gathering.
Daniel Ratcliffe, inspector of ancient monuments at Historic England South West, said: “Two circuits of stone-built ramparts survive at Stowe’s Pound within which there are remains of house platforms and cairns and it is from these ancient archaeological features that many of the stones are being taken to construct the inevitably temporary ‘fairy castles’, an increasingly common sight at beaches around the world.
“This movement of stones, whilst it may seem benign, is eroding the nationally protected archaeological features of the site as well as its local distinctiveness. We would encourage visitors to take only photographs of, and to leave only footprints at, this very precious and unique site.”