Black and white 'capsule' on underside of common nettle leaf. I've never seen anything like it before.
No identification made yet.
No interactions present.
At this page -
Not necessarily the same beast, but possibly related.
Thanks a lot for the prompt response - it certainly looks very much like that so something along those lines looks likely. Thanks for the link.
I concur. This is most likely an Ichneumen Wasp pupa.
Here's another, very similar, clue http://dfwurbanwildlife.com/2013/06/30/insects/ichneumon-wasp-cocoon/
Lat/Lng: 51.6808, -3.6258
OS grid ref: SS876992
Scrubby area of bramble, nettle and rank grassland between well-used track and riparian tree-line.