What a whopper - as my dainty Birkenstocked foot, included in the picture for scale, shows.
This monster and a number of lesser monsters have sprung up around the base of our beech trees. My Glam.Ass. reached for his big book of Mushrooms and Toadstools and is now fairly certain it is Trametes versicolor. This is not good news. Firstly it is in the section dedicated to extremely poisonous varieties and is accompanied by a natty skull and crossbones symbol. Secondly he has decided it may sound the death knell for our trees as it prefers to live on dead wood.
Here we have another example of our differing outlooks on life. G.A. sees the tree as dying while I continue to see it flourishing, ie Not Dead Yet for Heaven's Sake.