Cyril Askew is the finder of this coin and I was asked to identify it and say what it might be worth. It’s a voided long cross penny of Henry III, specimens of which turn up quite regularly as detecting finds.
The coin is an example of class Va2. On the reverse the legend reads GIL BER TON CAN with some ligation. Therefore, the moneyer is Gilbert and the mint is Canterbury. The full name of this moneyer was Gilbert of Bonnington and he struck coins for the Archbishop of Canterbury.
The flan is slightly irregular, it has flat areas on both sides and the obverse is double struck (note the inner circle being out of line). In its present condition I’d price this Henry III penny no higher than £30.