A mating pair of Marbled White Butterfly
The brown markings of the female are quite obvious in this image below.
In fact the species is more closely related to the various 'Brown' species rather than its name suggests.
As is often the case there is always another male trying to get in on the act.
The flight time of this species is between mid June and the end of July.
I have found it just about everywhere I go in my area at the moment.