Joe Pearson asked me to identify this coin and provide a valuation. It’s a silver sceatta but Continental rather than an Anglo-Saxon issue.
On the obverse is a standard (a beaded square with a ring-and-dot centre and lines in the angles) and on the reverse a cross pommee surrounded by a pseudo legend. Therefore, this is a Continental sceatta of series D, type 8, which is number 793 in the Standard Catalogue.
A large number of this type must have come into England, for examples are found quite regularly. This one would grade about VF but there is some deposit in the background on both sides. In its present condition I’d price this coin at £60 – £70.