Stone fly nymph.
Sounds good to me
it looks like the large one that is common in the Don (perlodes microcephala, if i'm right
)
not sure if i could sex it though.
The males don't grow proper wings if i remember rightly and its only the females that fly.
Not sure if you can tell difference at Nymph stage
and the picture might make it look a bit darker than it is, nice image though
Often called Creepers or gadgers and used as bait sometimes (quite common to do this many moons ago)
Sandy