Counterfeit coin of the realm - Review and case study analysis

摘要

During July 2003 a Treasury representative stated in a Parliamentary answer that analysis on a sample of one pound coins collected in late 2002, showed that approximately one percent were counterfeit. With the Royal Mint estimate of some 1410 million pound coins in circulation (2003-2004), it follows that approximately 14 million were counterfeit. There are two main types of one-pound counterfeits in circulation within the UK: the first comprise cast lead or tin based 'coins' coated with brass; the second are struck brass 'coins'. The lead or tin variety can vary in quality but wear rapidly usually look, feel and sound completely wrong and are eventually identified by the banks and Post Office where they are withdrawn from circulation. Therefore the vast majority of counterfeit 1.00 pound coins currently in circulation are of the struck brass (or nickel-brass) form. Of these some will also be easy to detect if made of the wrong metal or details of the design look too crude and coarse. However, there is a particular struck counterfeit in circulation where the quality is such that bank sorting machines and tellers cannot identify these pieces. Both cast and struck counterfeit coinage is reviewed, along with a case study analysis of each method, attention being focused on the high quality struck nickel-brass copy.