This is a member of the Blue family of Butterflies, of which there are a large number in Europe.

About 9 different ones occur in Britain, of which 3 are often seen in the Stewkley area.

With the wings closed it is very difficult to tell the Argus Brown from the Common Blue, but when basking with the wings open the upper wings are brown.
It was identified from a photograph in 2009, where the differences were able to be studied.

The main food source is Rockroses, Storksbill, or Geranium.