How do we stop the vile BNP?

This is something I have been musing over, in a somewhat depresses way, over the last few days. Is merely pushing the main political parties enough? I don't know why people vote for the BNP but I want to know. Is it that they don't understand their policies and think they're just another ordinary party? I can't believe this. I can't believe people don't see they're not on the national stage and don't see the main parties talking about how vile they are. Is it because they see it as a protest vote, with no other party talking about what concerns them (either through lack of knowledge or fear of causing offence)? If so then the main parties have to identify those concerns and deal with them. But I'm not convinced this would be enough or that it would happen. It's a very worrying state of affairs...