The nearest I can find doing a reverse image search is a black-clouded longhorn beetle, but it doesn't look quite the same as it has bars across its back which I can't see in the photo of the one I saw. I saw it in Fort Augustus in the Scottish Highlands.
Thanks for any help anyone can give me.
Hi Nina,
What a spectacular critter. I'm no expert but after a bit of research in my insect book I think it might be a Timberman Beetle (Acanthocinus aedilis). It breeds in dead pine stumps and timber in northern areas so right habitat.