HYACINTH : hyacinthoides non-scripta white
We know this plant as the "white bluebell". When seen here, it is essentially a hybrid with the paler Spanish one, but is essentially the same plant. You may also find some that are pink.
Bluebells and their hybrid counterparts are discussed more fully here : BLUEBELLS
The white ones are equally attractive even though we may find them less dramatic and perhaps think of them as imposters.
NATIONAL TRUST : https://www.nationaltrust.org.uk/discover/nature/trees-plants/a-guide-to-bluebells-in-the-uk