The Copper Underwing (Amphipyra pyramidea) is very similar to the Svensson's Copper Underwing (Amphipyra berbera) and identification can sometimes be very difficult, especially in worn specimens.
The underside of the hindwing is the most reliable feature (A. pyramidea has a pale area in the centre) but is not obvious if you don't turn the species around.
Less reliable features are the following:
1. the markings on the upperside of the forewing tend to be more distinct in A. pyramidea;
2. the two black V's of the ante-median line are level in A. pyramidea and not level in A. berbera;
3. the labial palps of A. pyramidea usually have a whitish stripe; A. berbera has dark palps with pale tips.

1st & 2nd photo: In my yard, Hilversum, The Netherlands, 20 August 2012
3rd, 4th & 5th photo: Caught in my self made moth trap. In my yard, Hilversum, The Netherlands, 19 August 2018