A bronze Celtic? unit measuring 15 mm in diameter and 2 mm thick weighing 5 grams. As with most of these coins the reverse is dished slightly.
The obverse has a head facing left with pointed features and beard and what appears to be either a braided hairstyle or some sort of cap. The reverse shows a boar walking right with a horizontal line beneath and what appears to be some lettering above, now indecipherable.
My FLOT states that this looks like a “Massalia Bull” unit, an import from southern Gaul, 250-150 BC. These are basically the inspiration for all the Kentish Potins produced afterwards. It’s a very important coin; they are rare finds in this country.
There is one other example on the PAS database: ESS-5BFC67
It will be going for recording shortly.