Most of these are Quaking Grass (Briza media)  stems with the purple heart shaped flowers quaking or quivering in the breeze.  It is an attractive little plant found mainly on old grassland with many local names like Totter Grass, Trembling Grass, Wag-wantons, Wibbly-wobbly, Shivery Shaky Grass.
 The more delicate slender flowers are those of Wood melick (Melica uniflora) which grows in dense brilliant green patches with dark egg shaped spikelets containing the tiny flowers and is an indicator that the local wood is ancient woodland.  I am not aware of having seen it very often but was pleased to find it.