This coin was unearthed very recently by Martin Depear. At first sight it is a straightforward voided long cross penny of Henry III. However, it soon becomes apparent that it isn’t
On the obverse the king holds a sceptre, so this side is one of the class 5 types. On closer inspection the uprights of the letters are all thicker than usual and the head doesn’t match any of those known for class 5. On the reverse the legend reads AD ONL VND EN. Therefore, this is supposed to be a penny of London but the moneyer’s name is made up of only two letters: A and D. This might be interpreted as an abbreviated form of ADAM but it can’t be as a moneyer of that name was not an official at the mint situated in London.
All the anomalies just mentioned add up to this coin being a Continental imitation of a Henry III voided long cross penny. The design is based upon class 5 but some of the features are incorrect, especially the legend on the reverse.
As a Continental imitation, is this coin worth less than a genuine penny of Henry III? Well, in actual fact it is worth a bit more. Lots of imitations were imported into England but they are certainly rarer than official English coins. Basic design anomalies make some fairly easy to identify, whilst others copy more closely the official issues and these can be very difficult to spot. Exporting these things to England could be profitable, as they were light in weight and/or not up to the sterling standard.
Martin’s find would grade about VF and to a keen collector it should be worth at least £80.