A rust on Wood Anemone.  There are no aecia or uredinia, and no host alternation; dark brown telia are present, mainly on the leaf undersides.  The teliospores are two-celled, soon breaking apart, and are spiney/warty.

host

Photograph the rust on the host plant; ensure you have noted the host species in your comments.  This is rarely recorded in Leicestershire and Rutland, and we recommend that you retain a specimen for verification.

Woodlands, on Amenome nemorosa

Scarce