Photo © Andy Mitchell
Xanthorhoe biriviata, the balsam carpet, is a moth of the genus Xanthorhoe in the family Geometridae. The species was first described by Moritz Balthasar Borkhausen in 1794. It is found "widespread in Europe and temperate Asia. In southern Europe the distribution is restricted only locally to the mountain(s)."
Source: Wikipedia
The primary larval foodplants are Orange Balsam (Impatiens capensis) and Small Balsam (Impatiens parviflora).