Here are a couple of before and after images of Boslow Inscribed Stone, St Just, Cornwall.
Fortunately the Boslow site is being monitored by CASPN (Cornish Ancient Sites Protection Network) in conjunction with Cornwall Council’s Historic Environment Service Officer who has already spoken to the farmer.
However, there are many thousands of ancient sites elsewhere which don’t have protection networks and are far more vulnerable. Budgetary constraints can mean that unless they are alerted to a problem Historic England inspectors may not be able to visit more than once in several years, if at all. (The parlous financial reality surrounding all heritage guardianship is something which those who complain about having to pay to go to Stonehenge should perhaps take on board!)
So it’s pretty clear that conservation is often in the hands of the general public who are in a position to alert official guardians to problems as soon as they arise.