You should never eat any fungi or mushrooms without getting expert identification. Many mushrooms are lethally poisonous. Do not rely on this site for identification - I am not an expert.
Photograph: Wildgrounds, Gosport, 17th October 2002.
These are large bracket fungi. I think it they are a Ganoderma sp., possibly G. applanatum as the flesh was thin.
The large entire portion measured about 40cm across, the lens cap, a black blob on top of it, is 5cm across.