Galanthus nivalis - Snowdrop
The Snowdrop is a distinctive flower that is usually one of the first flowers of the season.
The commonest is Galanthus nivalis. This has a grey-green leaves, usually less than 6mm across and at the leaf-base, they face each other, rather than one wrap around the inner one.
There are many introduced species and cultivars that can be distinguished brighter green, wider leaves and by the arrangement of the inner and outer “petals” and the markings, . For more information see this video or this identification sheet from the BSBI.