Archaeologists claim so, at least in Jasper Copping’s article in the Sunday Telegraph. They claim the practice, called “nighthawking”, is destroying context in a number of protected sites. These detectors then sell the works on the internet or eBay. These claims of antiquities transactions on the internet are thrown about a great deal, but I’m aware of no concrete study or even much in the way of supporting evidence of this claim, though there are sometimes anecdotal claims which are thrown about.
It seems that English Heritage and the British Museum have commissioned a £100,000 study into the scope of the activity, which might lead to new legislation to deal with offenders.
There certainly are problems with the Dealing in Cultural Objects Offences (Act), which makes it difficult to establish wrongdoing when purchasers do not inquire into an object’s provenance. If new legislation is forthcoming, to be truly effective it needs to pinpoint the difficulty in regulating good faith purchasers, and raise the bar for the inquiry which must go into their decision to buy.
The nighthawking problem does reveal why protecting rural and historic sites can be so difficult. The Treasure Act has problems to be sure, but I have argued that it is a good and pragmatic compromise between archaeologists and antiquities collectors. When qualifying treasure is found under the Treasure Act (which applies only to England and Wales), finders are required by law to report the finds, and are rewarded for doing so. The forthcoming study will be interesting, and the actions by these unscrupulous detectors may run the risk of destroying the delicate compromise which the Treasure Act has created.