Sedges have edges.
Rushes are round.
Grasses are hollow,
Right up from the ground.

This simple rhyme can help you work out what kind of grass-like plant you are looking at.

This plant is a pendulous sedge, so called because it’s flowers and seed heads droop downwards rather than standing erect. Watch out if you touch it, it’s edges can be sharp!
It likes damp and shady places in the wood.
we have another sedge here as well called wood sedge (Carex sylvatica)