I came across one of these guys just at the entrance to the cabin in my garden the other day.
I thought I had seen most insects but it's the first time I had seen this type and it was definitely not very friendly looking.
When it arched its back like a scorpion and I spotted the pincers I thought better of lifting it up.
It was about 25mm long.
Billy
www.youtube.com/watch?v=6vkiCE9lr6o (http://www.youtube.com/watch?v=6vkiCE9lr6o)