Amanita muscaria - or fly amanita is poisonous. This one was amongst a number popping up out of the undergrowth. As I was carefully kneeling on the ground to take photo one of the gardners wandered by and commented that it would be one of the most photographed fungi in the world. Last year I found one that was a brilliant red but on questioning the gardner apparently this is a slightly different variety and doesn't have that rich color. They appear like little white eggs popping up through the undergrowth and develop into quite large mushrooms. They apprently were used by the Vikings before going into battle for there phsycho producing abilities.