In AD 43 Britain was invaded and conquered under Claudius. Apparently, thereafter the demand for coins far exceeded the official supply and locals began minting imitations of AE prototypes of Claudius. Compare this original to its imitation: TI CLAVDIVS CAESAR AVG PR TRP IMP PP /S C on either side of Minerva brandishing spear in right, holding shield in left 28 mm. Die axis: 6:30. RIC 116. BMC 207. Struck c. 50-54. RIC I, 100, plate 16 says "weight peak c. 11.25 - 9.50 grams." British imitation. 24 mm. 6:00. 3.93 grams. Thin flan. No legible letters, nose weak. /Clear Minerva, bold S C. I have an educational web page on imitations of coins of Claudius: http://esty.ancients.info/imit/imitclaudius.html They may be uncommon in the US, but they are common in England.
This approach to fourees is more like US Civil War Tokens... This makes sense as opposed to counterfeiting.