This beetle is rather distinctive as the elytra (the hard bit that covers the wings) has a quite strong violet tinge - particularly around the edge where there is a thin flange. It is a common beetle, but may not be seen very often, as it hides away during the day, emerging at night to eat slugs and other invertebrates. I spotted this one during a conservation task in the woodland area, when we were clearing a glade, and presumably we cleared away the hiding place of this fellow.
It is part of the Carabus family of beetles and the second photo is another Carabus beetle, but I am not sure it is actually the Violet Ground beetle - becasue it doesn't exhibit the same violet tinge. You can see it is very similar, but it does look different