Weasels, Stoats or possibly depending on where you live Minks - as pointed out earlier NOT a raccoon in the UK.
Weasels are hard to see, they are so small. Even stoats are only likely to be seen darting across a road. They both shoot about in undergrowth at an alarming speed.
Weasels will get through less than a 1 inch hole, Stoats can probably manage to get through a 1 inch hole, Minks are a bit bigger.
Either way, here's a link to a post with details of making a weasel trap.
I'm not sure where you'd buy leg traps in the UK anymore - maybe you'd need to get them from the internet.