Heart and Dart.
(Agrotis exlamationis)

On a rough stone wall.

Information:
Quite small as the length of its Fore-wing is 15-19mm. It is extremely variable in its brown-based colouring but has a distinctive dark 'Heart' and 'Dart' marking on each wing. It can be confused with the Heart and Club, Great Dart and the Turnip moth but a reasonably constant diagnostic feature is the black mark across its 'collar'.
Flying May-September they can be seen almost everywhere except on mountains.