The other link was more interesting to me and relavent to Martin Gibson's comments. Here is part of the first post.

The owner of the Bevo Mill on Monday canceled a folk music festival scheduled for this weekend after learning that the event was affiliated with the National Alliance, considered one of the nation's biggest neo-Nazi groups.

It seems from that that the US has the same problem as the UK... Perhaps worse, and for longer - the BNP only seems to have moved into folk music recently and contary to what Martin says, it doesn't extend into a good deal of the British folk scene although I don't think they will be going away in a hurry.