Oyster Mushroom - Pleurotus ostreatus

The shell-like or fan-shaped cap is very variable in size, shape and colour - white, blue-grey, cream, brown, pinkish - but it always has an eccentric stipe. The gills are white, crowded and decurrent.   

other Pleurotus. 

Photograph from top down, in side-view and underneath to show gills and stipe attachment; not substrate and habitat

They grow on dead wood - usually on dead standing trees or on fallen logs.

It can be seen for most of the year especially late spring to autumn.

Fairly common and widespread in Britain.

Fairly common in Leicestershire and Rutland.