Carabus problematicus

It can be difficult to differentiate between this magnificent fellow and the very very similar Violet Ground Beetle (Carabus violaceus) but I've settled the problem based on size and the slight dimpling to the elytra (fused wing casings).
Whilst they are a mostly nocturnal predator (great to have in your garden as they're favourite food is slugs) this one was amazingly lively - this is the only shot I got that was anywhere near in focus.