A New Addington grandmother who believed she had been in possession of a Roman coin for the past 25 years has been told her artefact is a "very clever fake" by a local archaeologist.

Despite Iris Slocombe's coin having near-perfect detail on one side, the other side was factually incorrect and gave it away as a copy.

An expert from Croydon Natural History and Scientific Society said Mrs Slocombe's suspected prehistoric fossilised sea urchin was authenticated as a genuine artefact.