Its funny, I had been expecting to ask if you knew the connection between these three photos (other than all being taken at Sandhouse Lane NR today):
The top one is Chrysis viridula, a cuckoo wasp of the ground-nesting species Odynerus spinipes and Odynerus melanocephalus.
The middle one is a chimney on top of a nest made by a female of one of these two Odynerus species, but I don't know which as I didn't see a wasp using it.
I was expecting to say that the bottom photo was a male of one of the two Odynerus species, but when I checked the ID it actually keyed out as Gymnomerus laevipes a species that nests in stems like bramble and has no connection with either of the other two photos after all!
It just underlines the need to check details closely and not jump to conclusions. (Hopefully I have these IDs right and won't find that I actually needed to check them even more closely...!)