It's not actually a crocus - common names aren't always a good indicator. Colchicum autumnale is a member of the Lily family.
The plants are poisonous but apparently not the usual source* of Colchicine which is used in biochemical research
and is definitely present in the bulbs. Colchicine has been used (and may still be) for the treatment of gout.
Nor is this flower the source of Saffron -
see Crocus sativus for that !)
Velvet Bottom, growing amongst bracken on a south facing meadow.
The site in the spring, bracken has died back and the Autumn Crocus leaves are dominant among bluebells. (There is no
confusing "Autumn Crocus" with real crocuses when the leaves are out.)