Used in conjunction with modern archeological techniques metal detectors are a useful tool., and are great fun on the beach coinshooting. The chap who found the Staffordshire hoard collected useful data and informed the portable antiquities scheme too - a credit to the hobby. Unfortunately in the wrong hands they have the potential to do real damage; nighthawking and other illegal metal detectorist activity is the scourge of British archeology. If finds are simply dug up without recording their location and context then they are rendered worthless.

I dread to think how much of our shared heritage goes straight to eBay.