This counter is based upon published figures from academic studies, the Portable Antiquities Scheme and the comprehensive survey of finds rates recently carried out by detectorists and published on the premier UK discussion forum.

The figures are deliberately conservative relative to documented evidence. For example, both detectorists’ and independent estimates and surveys of the total rate of artefact removal have suggested rates up to nearly 40% higher than indicated here (well over 100,000 artefacts per annum more). A collection of 20,000 artefacts, mainly non-metallic and found on an "eyes only" basis by a single detectorist over 11 years, was recently offered for sale on eBay.

In addition, the number of active detectorists assumed here, 10,000, is by far the lowest of all estimates. Recently published estimates, all by very prominent detectorists, have been 20,000, 30,000, 60,000, 100,000 and 250,000. A study during the 1980s put the figure at 180,000. In addition, neither the above estimates nor this counter reflect the impact of the overseas visitors who are attracted here to detect under liberal British laws which are often in sharp contrast to the situation in their home countries. The numbers are unquantifiable but it is known that very significant numbers of European detectorists regularly attend British metal detecting rallies whilst many North American detectorists take part in organised “detecting holidays” and tours. Finds from one holiday operation run into thousands.

Since what happens in the fields is essentially a secret known only to each individual detectorist, no-one can claim to know for certain the true figures or suggest any particular estimate is right or wrong. Consequently, our purpose in presenting this counter is to illustrate to the public in a clear way that even on the basis of the lowest likely estimates the rate of erosion of the finite resource is unacceptable – and is happening in Britain and almost nowhere else.

The counter may or may not be a precise reflection of the rate of depletion. The broad picture it paints, of millions of artefacts being progressively removed and society being deprived of the associated knowledge of its past, is certainly accurate.

It should be noted that the rate of loss illustrated by the counter varies, being much reduced during the hours of darkness, for obvious reasons.