I was working on a construction site for new houses in the Bridgend area of south wales when this little fella landed on some timber I had just fitted and was walking along the timber and each time it came to a hole where a nail had been punched in it would stick its head in, raise its body vertical but the long tail part would not go in the air like the body but would point down, I couldn't get close enough to see what it was doing and i had never seen one before so I was hoping someone could let me know, many thanks.
It is a female wood wasp or ichneumon wasp. They are curious about dark holes, since such places may offer sites for nests. However, the behaviour of pointing the pointed end (ovipositor) downwards suggests she is interested in egg laying, potentially in a grub that might be inhabiting one of those holes.
We may get a comment refining or correcting my comments above, from one of the folks who know more about these insects than I do.
Thanks for taking the time to answer my question mike, I had a look at a few pictures after knowing what to search and found the exact one, with an explaining of it being a female just like you said, much appreciated
Hmm, a wood wasp and an ichneumon aren't the same thing. In fact some ichneumons such as Rhyssa, parasitise wood wasp larvae. Perhaps this is Rhyssa though I think it looks more like Gasteruption - but I'm not sure.