'Sam Hudson' seems to have reappeared on Facebook, posting more abusive and threatening messages. I've reported and blocked him/her there, but it's a shame the same can't be done here - if there is anything posted on livejournal about Keith I very much doubt that it comes from the people SamH claims.
Personally I think immigration is a legitimate concern for anyone, but because of the way it has been hijacked by neo-Nazi parties, the facts are crucial. People vote BNP because of a perception rather than any hard evidence or tested policy, and they need to be swayed by irrefutable evidence.
As Joe says, people are afraid for their jobs and their physical safety. Yes, we know those fears are misplaced, but it does the voice of reason no favours if anyone merely mentioning them is met with abuse and allegations of dishonesty. Keith is not a racist or a fascist - he is merely articulating what I imagine a huge number of people in Britain feel. If that is simply shouted down and written off as racism or ignorance then the battle against the BNP is probably lost.