Carex canescens White Sedge C DD N
The flowers in the early stages are supposed to be greenish white hence the name White Sedge but they don't look very pale to me. This is very common in Northern England, Wales, Scotland and a few outposts in Southern Counties but quite uncommon in Central England. It is a plant of the acid, boggy ground like many of our sedges. Forgive the background: the wind was extra strong so someone held while I clicked. I was quite amazed to get any sharpness at all from the photo.
The name has recently changed (New Flora of the British Isles Third Edition by Clive Stace 2010) from Carex curta to Carex canescens.