Found in the UK at keele university in staffordshire
Lately I've been trying to id grasses and sedges...this looks like a sedge....are the stems triangular, i.e. with edges? Sedges have edges! I'm sure someone else will narrow down the possibilities!
You could google Carex ( sedge genus) and see if it looks like any of these.
Carex pendula - very common UK sedge. And the thin cylindrical ones will be Juncus effusus. Repeat post and the answer is the same.
Here is a link that might be useful: Duplicate post