I love mushrooms. As an alternative to cheese (one of my other loved foods), I love mushroom sandwiches too. Bread is of course my other loved food. Yes, I'm a cheese sandwhich junkie first, mushroom sandwich junkie second.
Imagine my joy when walking through the woods to find this beauty. I've heard it said that most mushrooms in the UK are OK to eat... fortunately I don't think 'most' is anywhere near a good enough probability ratio to experiment with. I did spend 10 minutes on my PDA accessing the internet to identify it but gave up and carried on walking. Having now looked up what this mushroom is, it's an Amanita Muscaria and the website of "Rogers Mushrooms" give it an edibility rating of "Deadly".
Perhaps the bright red cap with white spiky bits on top of the red are natures way of telling me "Red is danger, spiky bits mean danger too so you really don't want to eat me Steve!", that and I thought it looked like a friendly cartoon mushroom far to good to eat, happily growing in tree dappled sunshine.
Update: Steve in the comments section posted a link to a YouTube video from BBC Worldwide talking about this mushroom