As is often the way with fungi... there are others that resemble these.
I have eaten milk caps but wouldnt trust myself to ID them properly any more.
Mostly found under pines rather than birch.
These look far too old to be of any use, the white stain on the gills is rot of some kind indicating how old they are.
Uncommon in the South this tasty mushroom is more frequent in Scotland and Northern Britain.
www.wildfooduk.com