This isn't my image, a Failbook contact posted it so I thought I'd see what the Illuminati of BCUK would come up with as there's no consensus elsewhere yet - it's the only image I have and there's no spore print I'm afraid:
A picture of the gills is needed at the very least for anyone to make a remotely confident ID. It looks like some kind of Bolete (assuming it was growing near trees) from the stem and the flesh that is visible through the eaten parts of the cap. But it could be just an illusion and i could be completely wrong.