Raft Spider - http://www.flickr.com/photos/qwertyqwertyqwerty/
The Raft Spider (Dolomedes fimbriatus), or Swamp Spider is a large spider
Quite rare in Britain, this species is found in the South of Britain, where there are decent sized populations in places such as those in the New Forest in Hampshire, and Arne in Dorset. This large spider has a body length of about 25mm, and is easily identified by it's chestnut coloured body and legs, with two cream stripes running down.
This species feeds on invertebrates, tadpoles and even fish. This species hunts by sitting on the surface of a pond or pool, waiting to pick up vibrations from the surface. If alarmed this species will dive underwater, creating a air bubble.