The cap is campanulate or conical, and pinkish-brown to purplish-brown.  Gills are white or pale purplish; stipe is dark purplish brown, pruinose.  The cap, gills and stem bleed a purplish-red juice when cut or bruised.  

Mycena sanguinolenta also exudes reddish fluid but has a delicate, striate cap; it is associated with conifer woodlands. 

dark red fluid 

Photograph from top down, in side view and from underneath to show gills, dark red staining or 'mik', and full length of stipe.  Note habitat and substrate.

Broad-leaved woodland, on standing or fallen wood or stumps

June to November.

fairly frequent

Status in Leicestershire and Rutland not known.

https://www.first-nature.com/fungi/mycena-haematopus.php